diff --git a/src/PhpFile.php b/src/PhpFile.php
index 0b4deac..055a696 100644
--- a/src/PhpFile.php
+++ b/src/PhpFile.php
@@ -16,8 +16,8 @@ class PhpFile extends DependencyAwareGenerator
     protected string   $name;
     protected ?Comment $comment;
 
-    /** @var PhpClass[] */
-    protected array $classes = [];
+    /** @var OOPStructure[] */
+    protected array $oopStructures = [];
 
     /** @var string[] */
     protected array $declares = [];
@@ -25,7 +25,7 @@ class PhpFile extends DependencyAwareGenerator
     public function __construct(string $name = '')
     {
         $this->name = $name;
-        $this->dependencyAwareChildren = [&$this->classes];
+        $this->dependencyAwareChildren = [&$this->oopStructures];
     }
 
     public static function new(string $name = ''): self
@@ -36,12 +36,12 @@ public static function new(string $name = ''): self
     public function generate(): string
     {
         $namespace = $this->namespace ? "\nnamespace $this->namespace;\n" : '';
-        $classes = implode("\n\n", $this->classes);
+        $oopStructures = implode("\n\n", $this->oopStructures);
 
         return <<<CODE
         <?php
         $namespace{$this->buildUseStatements()}
-        $classes
+        $oopStructures
         CODE;
     }
 
@@ -50,38 +50,92 @@ public function __toString(): string
         return $this->generate();
     }
 
+    public function removeOOPStructure(string $name, ?string $type = null): self
+    {
+        foreach ($this->oopStructures as $key => $oopStructure) {
+            if ($oopStructure->name === $name && ($type === null || $oopStructure instanceof $type)) {
+                unset($this->oopStructures[$key]);
+            }
+        }
+
+        return $this;
+    }
+
+    public function getOOPStructure(string $name, ?string $type = null): ?OOPStructure
+    {
+        foreach ($this->oopStructures as $key => $oopStructure) {
+            if ($oopStructure->name === $name && ($type === null || $oopStructure instanceof $type)) {
+                return $this->oopStructures[$key];
+            }
+        }
+
+        return null;
+    }
+
     public function addClass(PhpClass $class): self
     {
-        $this->classes[] = $class;
+        $this->oopStructures[] = $class;
 
         return $this;
     }
 
     public function createClass(string $name): PhpClass
     {
-        return $this->classes[] = PhpClass::new($name);
+        return $this->oopStructures[] = PhpClass::new($name);
     }
 
     public function removeClass(string $name): self
     {
-        foreach ($this->classes as $key => $class) {
-            if ($class->name === $name) {
-                unset($this->classes[$key]);
-            }
-        }
+        return $this->removeOOPStructure($name, PhpClass::class);
+    }
+
+    public function getClass(string $name): ?PhpClass
+    {
+        return $this->getOOPStructure($name, PhpClass::class);
+    }
+
+    public function addTrait(PhpTrait $trait): self
+    {
+        $this->oopStructures[] = $trait;
 
         return $this;
     }
 
-    public function getClass(string $name): ?PhpClass
+    public function createTrait(string $name): PhpTrait
     {
-        foreach ($this->classes as $key => $class) {
-            if ($class->name === $name) {
-                return $this->classes[$key];
-            }
-        }
+        return $this->oopStructures[] = PhpTrait::new($name);
+    }
 
-        return null;
+    public function removeTrait(string $name): self
+    {
+        return $this->removeOOPStructure($name, PhpTrait::class);
+    }
+
+    public function getTrait(string $name): ?PhpTrait
+    {
+        return $this->getOOPStructure($name, PhpTrait::class);
+    }
+
+    public function addInterface(PhpInterface $trait): self
+    {
+        $this->oopStructures[] = $trait;
+
+        return $this;
+    }
+
+    public function createInterface(string $name): PhpInterface
+    {
+        return $this->oopStructures[] = PhpInterface::new($name);
+    }
+
+    public function removeInterface(string $name): self
+    {
+        return $this->removeOOPStructure($name, PhpInterface::class);
+    }
+
+    public function getInterface(string $name): ?PhpInterface
+    {
+        return $this->getOOPStructure($name, PhpInterface::class);
     }
 
     public function getNamespace(): string
diff --git a/tests/PhpFileTest.php b/tests/PhpFileTest.php
index b61ff58..ae90cfd 100644
--- a/tests/PhpFileTest.php
+++ b/tests/PhpFileTest.php
@@ -11,6 +11,9 @@
 use Murtukov\PHPCodeGenerator\Modifier;
 use Murtukov\PHPCodeGenerator\PhpClass;
 use Murtukov\PHPCodeGenerator\PhpFile;
+use Murtukov\PHPCodeGenerator\PhpInterface;
+use Murtukov\PHPCodeGenerator\PhpTrait;
+use Murtukov\PHPCodeGenerator\Property;
 use Murtukov\PHPCodeGenerator\Qualifier;
 use PHPUnit\Framework\TestCase;
 
@@ -167,7 +170,7 @@ public function modifyComments(PhpFile $file): PhpFile
      * @test
      * @depends modifyComments
      */
-    public function saveFile(PhpFile $file): void
+    public function saveFile(PhpFile $file): PhpFile
     {
         $path = sys_get_temp_dir().'/PHPCodeGenerator/GeneratedFile.php';
 
@@ -189,5 +192,165 @@ public function saveFile(PhpFile $file): void
 
         // @phpstan-ignore-next-line
         $this->assertEquals(['status' => 200], $yetAnotherClass->getArray());
+
+        @unlink($path);
+
+        return $file;
+    }
+
+    /**
+     * @test
+     * @depends saveFile
+     */
+    public function modifyFileClassToTrait(PhpFile $file): PhpFile
+    {
+        $file->removeClass('YetAnotherClass');
+        $file->addTrait(new PhpTrait('TAnotherTrait'));
+
+        $this->assertNull($file->getClass('NonExistentClass'));
+        $this->assertEquals('App\Converter', $file->getNamespace());
+
+        $this->assertNotNull($file->getTrait('TAnotherTrait'));
+        $this->assertNotNull($file->getOOPStructure('TAnotherTrait'));
+        $this->assertInstanceOf(PhpTrait::class, $file->getOOPStructure('TAnotherTrait'));
+        $this->assertNull($file->getClass('TAnotherTrait'));
+        $this->assertNull($file->getInterface('TAnotherTrait'));
+
+        $this->expectOutputString(<<<'CODE'
+        <?php
+
+        namespace App\Converter;
+
+        trait TAnotherTrait
+        {
+        }
+        CODE
+        );
+
+        echo $file;
+
+        return $file;
+    }
+
+
+    /**
+     * @test
+     * @depends modifyFileClassToTrait
+     */
+    public function modifyFileAddAnotherTrait(PhpFile $file): PhpFile
+    {
+        $file->createTrait('TYetAnotherTrait')
+            ->append(Method::new('getName'));
+
+        $this->expectOutputString(<<<'CODE'
+        <?php
+
+        namespace App\Converter;
+
+        trait TAnotherTrait
+        {
+        }
+
+        trait TYetAnotherTrait
+        {
+            public function getName()
+            {
+            }
+        }
+        CODE);
+
+        echo $file;
+
+        return $file;
+    }
+
+
+    /**
+     * @test
+     * @depends modifyFileClassToTrait
+     */
+    public function modifyFileTraitToInterface(PhpFile $file): PhpFile
+    {
+        $file->removeTrait('TAnotherTrait');
+        $file->removeTrait('TYetAnotherTrait');
+        $file->addInterface(new PhpInterface('IAnotherTrait'));
+
+        $this->assertNull($file->getClass('NonExistentClass'));
+        $this->assertEquals('App\Converter', $file->getNamespace());
+
+        $this->assertNotNull($file->getInterface('IAnotherTrait'));
+        $this->assertNotNull($file->getOOPStructure('IAnotherTrait'));
+        $this->assertInstanceOf(PhpInterface::class, $file->getOOPStructure('IAnotherTrait'));
+        $this->assertNull($file->getClass('IAnotherTrait'));
+        $this->assertNull($file->getTrait('IAnotherTrait'));
+
+        $this->expectOutputString(<<<'CODE'
+        <?php
+
+        namespace App\Converter;
+
+        interface IAnotherTrait
+        {
+        }
+        CODE
+        );
+
+        echo $file;
+
+        return $file;
+    }
+
+
+    /**
+     * @test
+     * @depends modifyFileTraitToInterface
+     */
+    public function modifyFileAddAnotherInterface(PhpFile $file): PhpFile
+    {
+        $file->createInterface('IYetAnotherTrait')
+            ->createSignature('getName');
+
+        $this->expectOutputString(<<<'CODE'
+        <?php
+
+        namespace App\Converter;
+
+        interface IAnotherTrait
+        {
+        }
+
+        interface IYetAnotherTrait
+        {
+            public function getName();
+        }
+        CODE);
+
+        echo $file;
+
+        return $file;
+    }
+
+    /**
+     * @test
+     * @depends modifyFileAddAnotherInterface
+     */
+    public function modifyFileARemoveInterface(PhpFile $file): PhpFile
+    {
+        $file->removeInterface('IAnotherTrait');
+
+        $this->expectOutputString(<<<'CODE'
+        <?php
+
+        namespace App\Converter;
+
+        interface IYetAnotherTrait
+        {
+            public function getName();
+        }
+        CODE);
+
+        echo $file;
+
+        return $file;
     }
 }