diff --git a/icu4c/source/i18n/datefmt.cpp b/icu4c/source/i18n/datefmt.cpp
index b25312463e0..f653483b3f5 100644
--- a/icu4c/source/i18n/datefmt.cpp
+++ b/icu4c/source/i18n/datefmt.cpp
@@ -561,7 +561,7 @@ DateFormat::create(EStyle timeStyle, EStyle dateStyle, const Locale& locale)
     // This should never really happen, because the preceding constructor
     // should always succeed.  If the resource data is unavailable, a last
     // resort object should be returned.
-    return 0;
+    return nullptr;
 }
 
 //----------------------------------------------------------------------
diff --git a/icu4c/source/i18n/udat.cpp b/icu4c/source/i18n/udat.cpp
index e249be3aee9..439721bb9f0 100644
--- a/icu4c/source/i18n/udat.cpp
+++ b/icu4c/source/i18n/udat.cpp
@@ -142,7 +142,7 @@ udat_open(UDateFormatStyle  timeStyle,
 {
     DateFormat *fmt;
     if(U_FAILURE(*status)) {
-        return 0;
+        return nullptr;
     }
     if(gOpener!=nullptr) { // if it's registered
       fmt = (DateFormat*) (*gOpener)(timeStyle,dateStyle,locale,tzID,tzIDLength,pattern,patternLength,status);
@@ -186,7 +186,7 @@ udat_open(UDateFormatStyle  timeStyle,
         if(zone == 0) {
             *status = U_MEMORY_ALLOCATION_ERROR;
             delete fmt;
-            return 0;
+            return nullptr;
         }
         fmt->adoptTimeZone(zone);
     }