diff --git a/icu4c/source/test/intltest/callimts.cpp b/icu4c/source/test/intltest/callimts.cpp
index 7766d30ccc2..fe809478896 100644
--- a/icu4c/source/test/intltest/callimts.cpp
+++ b/icu4c/source/test/intltest/callimts.cpp
@@ -332,7 +332,7 @@ CalendarLimitTest::timeToFields(UDate theTime, int32_t* fields)
         
         // Compute the Julian calendar day number for January 1, rawYear
         //double january1 = 365 * (rawYear - 1) + floorDivide(rawYear - 1, 4);
-        double january1 = 365 * (rawYear - 1) + floorDivide(rawYear - 1, 4L);
+        double january1 = 365 * (rawYear - 1) + floorDivide(rawYear - 1, ((int32_t)4));
         dayOfYear = (int32_t)uprv_fmod(julianEpochDay - january1, 365.0);
         
         // Julian leap years occurred historically every 4 years starting
diff --git a/icu4c/source/test/intltest/numfmtst.cpp b/icu4c/source/test/intltest/numfmtst.cpp
index a45e98a7464..b5c97dede6f 100644
--- a/icu4c/source/test/intltest/numfmtst.cpp
+++ b/icu4c/source/test/intltest/numfmtst.cpp
@@ -453,7 +453,7 @@ void NumberFormatTest::TestSecondaryGrouping(void) {
     CHECK(status, "createInstance(hi_IN)");
 
     UnicodeString out;
-    int32_t l = 1876543210L;
+    int32_t l = (int32_t)1876543210L;
     g->format(l, out);
     delete g;
     // expect "1,87,65,43,210", but with Hindi digits
diff --git a/icu4c/source/test/intltest/numrgts.h b/icu4c/source/test/intltest/numrgts.h
index cc2779b0cff..20cae7ca144 100644
--- a/icu4c/source/test/intltest/numrgts.h
+++ b/icu4c/source/test/intltest/numrgts.h
@@ -135,7 +135,7 @@ public:
             Formattable&            result, 
             ParsePosition&          /* parsePosition */) const
     {
-        result.setLong(0L);
+        result.setLong((int32_t)0);
     }
   
     virtual void parse(    const UnicodeString&    text, 
diff --git a/icu4c/source/test/intltest/transrt.cpp b/icu4c/source/test/intltest/transrt.cpp
index 264f5a33842..3d32b565003 100644
--- a/icu4c/source/test/intltest/transrt.cpp
+++ b/icu4c/source/test/intltest/transrt.cpp
@@ -134,7 +134,7 @@ RTTest::RTTest(const UnicodeString& transliteratorIDStr,
     this->transliteratorID = transliteratorIDStr;
     this->sourceScript = sourceScriptVal;
     this->targetScript = targetScriptVal;
-    errorLimit = 0x7FFFFFFFL;
+    errorLimit = (int32_t)0x7FFFFFFFL;
     errorCount = 0;
     pairLimit  = 0x10000;
 }