diff --git a/README.md b/README.md
index cb9a9bd..95c9a70 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,10 @@ Methods
 
 **readInt32()** returns a 32-bit signed integer
 
+**readUInt64()** returns a 64-bit unsigned integer
+
+**readInt64()** returns a 64-bit signed integer
+
 **readSingle()** returns a 4-bytes floating-point
 
 **readUBits($length)** returns a variable length of bits (unsigned)
diff --git a/src/BinaryReader.php b/src/BinaryReader.php
index e30aa10..8e2d4a0 100644
--- a/src/BinaryReader.php
+++ b/src/BinaryReader.php
@@ -8,6 +8,7 @@
 use PhpBinaryReader\Type\Int8;
 use PhpBinaryReader\Type\Int16;
 use PhpBinaryReader\Type\Int32;
+use PhpBinaryReader\Type\Int64;
 use PhpBinaryReader\Type\Single;
 use PhpBinaryReader\Type\Str;
 
@@ -78,6 +79,11 @@ class BinaryReader
      */
     private $int32Reader;
 
+    /**
+     * @var \PhpBinaryReader\Type\Int64
+     */
+    private $int64Reader;
+
     /**
      * @var \PhpBinaryReader\Type\Single
      */
@@ -109,6 +115,7 @@ public function __construct($input, $endian = Endian::ENDIAN_LITTLE)
         $this->int8Reader = new Int8();
         $this->int16Reader = new Int16();
         $this->int32Reader = new Int32();
+        $this->int64Reader = new Int64();
         $this->singleReader = new Single();
     }
 
@@ -213,6 +220,22 @@ public function readUInt32()
         return $this->int32Reader->read($this);
     }
 
+    /**
+     * @return int
+     */
+    public function readInt64()
+    {
+        return $this->int64Reader->readSigned($this);
+    }
+
+    /**
+     * @return int
+     */
+    public function readUInt64()
+    {
+        return $this->int64Reader->read($this);
+    }
+
     /**
      * @return float
      */
@@ -435,6 +458,14 @@ public function getInt32Reader()
         return $this->int32Reader;
     }
 
+    /**
+     * @return \PhpBinaryReader\Type\Int64
+     */
+    public function getInt64Reader()
+    {
+        return $this->int64Reader;
+    }
+
     /**
      * @return \PhpBinaryReader\Type\Single
      */
diff --git a/src/Type/Int64.php b/src/Type/Int64.php
new file mode 100644
index 0000000..b1e4158
--- /dev/null
+++ b/src/Type/Int64.php
@@ -0,0 +1,120 @@
+<?php
+
+namespace PhpBinaryReader\Type;
+
+use PhpBinaryReader\BinaryReader;
+use PhpBinaryReader\BitMask;
+use PhpBinaryReader\Endian;
+
+class Int64 implements TypeInterface
+{
+    /**
+     * @var string
+     */
+    private $endianBig = 'N';
+
+    /**
+     * @var string
+     */
+    private $endianLittle = 'V';
+
+    /**
+     * Returns an Unsigned 64-bit Integer
+     *
+     * @param  \PhpBinaryReader\BinaryReader $br
+     * @param  null                          $length
+     * @return int
+     * @throws \OutOfBoundsException
+     */
+    public function read(BinaryReader &$br, $length = null)
+    {
+        if (!$br->canReadBytes(8)) {
+            throw new \OutOfBoundsException('Cannot read 64-bit int, it exceeds the boundary of the file');
+        }
+
+        $endian = $br->getEndian() == Endian::ENDIAN_BIG ? $this->endianBig : $this->endianLittle;
+        $firstSegment = $br->readFromHandle(4);
+        $secondSegment = $br->readFromHandle(4);
+
+        $firstHalf = unpack($endian, $firstSegment)[1];
+        $secondHalf = unpack($endian, $secondSegment)[1];
+
+        if ($br->getEndian() == Endian::ENDIAN_BIG) {
+            $value = bcadd($secondHalf, bcmul($firstHalf, "4294967296"));
+        } else {
+            $value = bcadd($firstHalf, bcmul($secondHalf, "4294967296"));
+        }
+
+        if ($br->getCurrentBit() != 0) {
+            $value = $this->bitReader($br, $value);
+        }
+
+        return $value;
+    }
+
+    /**
+     * Returns a Signed 64-Bit Integer
+     *
+     * @param  \PhpBinaryReader\BinaryReader $br
+     * @return int
+     */
+    public function readSigned(&$br)
+    {
+        $value = $this->read($br);
+        if (bccomp($value, bcpow(2, 63)) >= 0) {
+            $value = bcsub($value, bcpow(2, 64));
+        }
+
+        return $value;
+    }
+
+    /**
+     * @param  \PhpBinaryReader\BinaryReader $br
+     * @param  int                           $data
+     * @return int
+     */
+    private function bitReader(&$br, $data)
+    {
+        $bitmask = new BitMask();
+        $loMask = $bitmask->getMask($br->getCurrentBit(), BitMask::MASK_LO);
+        $hiMask = $bitmask->getMask($br->getCurrentBit(), BitMask::MASK_HI);
+        $hiBits = ($br->getNextByte() & $hiMask) << 56;
+        $miBits = ($data & 0xFFFFFFFFFFFFFF00) >> (8 - $br->getCurrentBit());
+        $loBits = ($data & $loMask);
+        $br->setNextByte($data & 0xFF);
+
+        return $hiBits | $miBits | $loBits;
+    }
+
+    /**
+     * @param string $endianBig
+     */
+    public function setEndianBig($endianBig)
+    {
+        $this->endianBig = $endianBig;
+    }
+
+    /**
+     * @return string
+     */
+    public function getEndianBig()
+    {
+        return $this->endianBig;
+    }
+
+    /**
+     * @param string $endianLittle
+     */
+    public function setEndianLittle($endianLittle)
+    {
+        $this->endianLittle = $endianLittle;
+    }
+
+    /**
+     * @return string
+     */
+    public function getEndianLittle()
+    {
+        return $this->endianLittle;
+    }
+}
diff --git a/test/BinaryReaderTest.php b/test/BinaryReaderTest.php
index 32a4d61..cd02d96 100644
--- a/test/BinaryReaderTest.php
+++ b/test/BinaryReaderTest.php
@@ -114,6 +114,21 @@ public function testInt32($brBig, $brLittle)
         $this->assertEquals(3, $brLittle->readUInt32());
     }
 
+        /**
+     * @dataProvider binaryReaders
+     */
+    public function testInt64($brBig, $brLittle)
+    {
+        $this->assertEquals(12885059444, $brBig->readInt64());
+        $this->assertEquals(8387672839590772739, $brLittle->readInt64());
+
+        $brLittle->setPosition(0);
+        $brBig->setPosition(0);
+
+        $this->assertEquals(12885059444, $brBig->readUInt64());
+        $this->assertEquals(8387672839590772739, $brLittle->readUInt64());
+    }
+
     /**
      * @param \PhpBinaryReader\BinaryReader $brBig
      * @param \PhpBinaryReader\BinaryReader $brLittle
@@ -321,6 +336,7 @@ public function testReaders()
         $this->assertInstanceOf('\PhpBinaryReader\Type\Byte', $brBig->getByteReader());
         $this->assertInstanceOf('\PhpBinaryReader\Type\Int16', $brBig->getInt16Reader());
         $this->assertInstanceOf('\PhpBinaryReader\Type\Int32', $brBig->getInt32Reader());
+        $this->assertInstanceOf('\PhpBinaryReader\Type\Int64', $brBig->getInt64Reader());
         $this->assertInstanceOf('\PhpBinaryReader\Type\Int8', $brBig->getInt8Reader());
         $this->assertInstanceOf('\PhpBinaryReader\Type\Str', $brBig->getStringReader());
         $this->assertInstanceOf('\PhpBinaryReader\Type\Single', $brBig->getSingleReader());
diff --git a/test/Type/Int64Test.php b/test/Type/Int64Test.php
new file mode 100644
index 0000000..f87db60
--- /dev/null
+++ b/test/Type/Int64Test.php
@@ -0,0 +1,119 @@
+<?php
+
+namespace PhpBinaryReader\Type;
+
+use PhpBinaryReader\AbstractTestCase;
+use PhpBinaryReader\BinaryReader;
+use PhpBinaryReader\Endian;
+
+/**
+ * @coversDefaultClass \PhpBinaryReader\Type\Int64
+ */
+class Int64Test extends AbstractTestCase
+{
+    /**
+     * @var Int64
+     */
+    public $int64;
+
+    public function setUp()
+    {
+        $this->int64 = new Int64();
+    }
+
+    /**
+     * @dataProvider binaryReaders
+     */
+    public function testUnsignedReaderWithBigEndian($brBig, $brLittle)
+    {
+        $this->assertEquals(12885059444, $this->int64->read($brBig));
+        $this->assertEquals(7310314309530157055, $this->int64->read($brBig));
+    }
+
+    /**
+     * @dataProvider binaryReaders
+     */
+    public function testSignedReaderWithBigEndian($brBig, $brLittle)
+    {
+        $brBig->setPosition(12);
+        $this->assertEquals(-3229614080, $this->int64->readSigned($brBig));
+    }
+
+    /**
+     * @dataProvider binaryReaders
+     */
+    public function testReaderWithLittleEndian($brBig, $brLittle)
+    {
+        $this->assertEquals(8387672839590772739, $this->int64->read($brLittle));
+        $this->assertEquals(18446744069975864165, $this->int64->read($brLittle));
+    }
+
+    /**
+     * @dataProvider binaryReaders
+     */
+    public function testSignedReaderWithLittleEndian($brBig, $brLittle)
+    {
+        $brLittle->setPosition(12);
+        $this->assertEquals(4575657225703391231, $this->int64->readSigned($brLittle));
+    }
+
+    /**
+     * @dataProvider binaryReaders
+     */
+    public function testBitReaderWithBigEndian($brBig, $brLittle)
+    {
+        $brBig->setPosition(6);
+        $brBig->readBits(4);
+        $this->assertEquals(504403158265495567, $this->int64->read($brBig));
+    }
+
+    /**
+     * @dataProvider binaryReaders
+     */
+    public function testBitReaderWithLittleEndian($brBig, $brLittle)
+    {
+        $brLittle->setPosition(6);
+        $brLittle->readBits(4);
+        $this->assertEquals(504403158265495567, $this->int64->read($brLittle));
+    }
+
+    /**
+     * @expectedException \OutOfBoundsException
+     * @dataProvider binaryReaders
+     */
+    public function testOutOfBoundsExceptionIsThrownWithBigEndian($brBig, $brLittle)
+    {
+        $brBig->readBits(360);
+        $this->int64->read($brBig);
+    }
+
+    /**
+     * @expectedException \OutOfBoundsException
+     * @dataProvider binaryReaders
+     */
+    public function testOutOfBoundsExceptionIsThrownWithLittleEndian($brBig, $brLittle)
+    {
+        $brLittle->readBits(360);
+        $this->int64->read($brLittle);
+    }
+
+    /**
+     * @dataProvider binaryReaders
+     */
+    public function testAlternateMachineByteOrderSigned($brBig, $brLittle)
+    {
+        $brLittle->setMachineByteOrder(Endian::ENDIAN_BIG);
+        $brLittle->setEndian(Endian::ENDIAN_LITTLE);
+        $this->assertEquals(8387672839590772739, $this->int64->readSigned($brLittle));
+    }
+
+    public function testEndian()
+    {
+        $this->int64->setEndianBig('X');
+        $this->assertEquals('X', $this->int64->getEndianBig());
+
+        $this->int64->setEndianLittle('Y');
+        $this->assertEquals('Y', $this->int64->getEndianLittle());
+    }
+
+}