diff --git a/modules/cfe_testcase/CMakeLists.txt b/modules/cfe_testcase/CMakeLists.txt
index 7606c6f64..0558a2f58 100644
--- a/modules/cfe_testcase/CMakeLists.txt
+++ b/modules/cfe_testcase/CMakeLists.txt
@@ -10,6 +10,7 @@ add_cfe_app(cfe_testcase
     src/fs_header_test.c
     src/sb_pipe_mang_test.c
     src/time_current_test.c
+    src/time_conversion_test.c
 )
 
 # register the dependency on cfe_assert
diff --git a/modules/cfe_testcase/src/cfe_test.c b/modules/cfe_testcase/src/cfe_test.c
index e9fa16c60..7cdb86562 100644
--- a/modules/cfe_testcase/src/cfe_test.c
+++ b/modules/cfe_testcase/src/cfe_test.c
@@ -59,6 +59,7 @@ void CFE_TestMain(void)
     FSHeaderTestSetup();
     SBPipeMangSetup();
     TimeCurrentTestSetup();
+    TimeConversionTestSetup();
 
     /*
      * Execute the tests
diff --git a/modules/cfe_testcase/src/cfe_test.h b/modules/cfe_testcase/src/cfe_test.h
index 0d8a77058..18487574f 100644
--- a/modules/cfe_testcase/src/cfe_test.h
+++ b/modules/cfe_testcase/src/cfe_test.h
@@ -81,5 +81,6 @@ void ESMemPoolTestSetup(void);
 void FSHeaderTestSetup(void);
 void SBPipeMangSetup(void);
 void TimeCurrentTestSetup(void);
+void TimeConversionTestSetup(void);
 
 #endif /* CFE_TEST_H */
diff --git a/modules/cfe_testcase/src/time_conversion_test.c b/modules/cfe_testcase/src/time_conversion_test.c
new file mode 100644
index 000000000..239599c10
--- /dev/null
+++ b/modules/cfe_testcase/src/time_conversion_test.c
@@ -0,0 +1,125 @@
+/*************************************************************************
+**
+**      GSC-18128-1, "Core Flight Executive Version 6.7"
+**
+**      Copyright (c) 2006-2021 United States Government as represented by
+**      the Administrator of the National Aeronautics and Space Administration.
+**      All Rights Reserved.
+**
+**      Licensed under the Apache License, Version 2.0 (the "License");
+**      you may not use this file except in compliance with the License.
+**      You may obtain a copy of the License at
+**
+**        http://www.apache.org/licenses/LICENSE-2.0
+**
+**      Unless required by applicable law or agreed to in writing, software
+**      distributed under the License is distributed on an "AS IS" BASIS,
+**      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+**      See the License for the specific language governing permissions and
+**      limitations under the License.
+**
+** File: time_conversion_test.c
+**
+** Purpose:
+**   Functional test of basic Time Conversion APIs
+**
+*************************************************************************/
+
+/*
+ * Includes
+ */
+#include "cfe_test.h"
+
+void TestConvertMET2SCTime(void)
+{
+    UtPrintf("Testing: CFE_TIME_MET2SCTime");
+
+    /* Mission Elapsed Time */
+    CFE_TIME_SysTime_t MET;
+    /* MET + SCTF */
+    CFE_TIME_SysTime_t TAI;
+    /* MET + SCTF - Leap Seconds */
+    CFE_TIME_SysTime_t UTC;
+    /* Spacecraft Time */
+    CFE_TIME_SysTime_t SCTime;
+
+    /* Print buffers */
+    char timeBuf1[sizeof("yyyy-ddd-hh:mm:ss.xxxxx_")];
+    char timeBuf2[sizeof("yyyy-ddd-hh:mm:ss.xxxxx_")];
+
+    /* Get Times */
+    MET = CFE_TIME_GetMET();
+    TAI = CFE_TIME_GetTAI();
+    UTC = CFE_TIME_GetUTC();
+
+    /* Convert - should produce a TAI or UTC at the moment of GetMET() */
+    SCTime = CFE_TIME_MET2SCTime(MET);
+
+    /* write Spacecraft Time into second buffer */
+    CFE_TIME_Print(timeBuf2, SCTime);
+
+    /* Check conversion */
+#if (CFE_MISSION_TIME_CFG_DEFAULT_TAI == true)
+    /* SCTime is TAI format */
+
+    /* avoid unused compiler warning */
+    (void)UTC;
+
+    /* write TAI into first buffer */
+    CFE_TIME_Print(timeBuf1, TAI);
+
+    UtAssert_True(CFE_TIME_Compare(TAI, SCTime), "TAI (%s) = MET2SCTime (%s)", timeBuf1, timeBuf2);
+#else
+    /* SCTime is UTC format */
+
+    /* avoid unused compiler warning */
+    (void)TAI;
+
+    /* write UTC into first buffer */
+    CFE_TIME_Print(timeBuf1, UTC);
+
+    UtAssert_True(CFE_TIME_Compare(UTC, SCTime), "TAI (%s) = MET2SCTime (%s)", timeBuf1, timeBuf2);
+#endif
+}
+
+void TestConvertSubSeconds2MicroSeconds(void)
+{
+    UtPrintf("Testing: CFE_TIME_Sub2MicroSecs");
+
+    /* predefined amount of sub-seconds */
+    uint32 SUB = 31000;
+    /* correct micro-seconds equal to the predefined sub-seconds */
+    uint32 ExpectedMS = 7;
+    uint32 Sub2Micro;
+
+    /* run Sub2MicroSecs with predefined amount of sub-seconds and save result */
+    Sub2Micro = CFE_TIME_Sub2MicroSecs(SUB);
+
+    UtAssert_UINT32_EQ(ExpectedMS, Sub2Micro);
+}
+
+void TestConvertMicroSeconds2SubSeconds(void)
+{
+    UtPrintf("Testing: CFE_TIME_Micro2SubSecs");
+
+    /* predefined micro-seconds */
+    uint32 MS = 64512;
+    /* predefined sub-seconds equal to predefined ms above */
+    uint32 ExpectedSUB = 277076931;
+    uint32 Micro2Sub;
+
+    /* convert and assert */
+    Micro2Sub = CFE_TIME_Micro2SubSecs(MS);
+    UtAssert_UINT32_EQ(ExpectedSUB, Micro2Sub);
+
+    /* assert for ms > 999999 >= 1 second  */
+    Micro2Sub = CFE_TIME_Micro2SubSecs(999999 + 1);
+    UtAssert_UINT32_EQ(0xFFFFFFFF, Micro2Sub);
+}
+
+void TimeConversionTestSetup(void)
+{
+    UtTest_Add(TestConvertMET2SCTime, NULL, NULL, "Test convert MET into spacecraft time");
+    UtTest_Add(TestConvertSubSeconds2MicroSeconds, NULL, NULL, "Test Convert sub-seconds into micro-seconds");
+    UtTest_Add(TestConvertMicroSeconds2SubSeconds, NULL, NULL, "Test Convert micro-seconds into sub-seconds");
+}