diff --git a/icu4c/source/i18n/number_longnames.cpp b/icu4c/source/i18n/number_longnames.cpp
index 0ec75ea0cc8..76d57a1b867 100644
--- a/icu4c/source/i18n/number_longnames.cpp
+++ b/icu4c/source/i18n/number_longnames.cpp
@@ -658,7 +658,7 @@ class DerivedComponents {
     UErrorCode status = U_ZERO_ERROR;
 
     // Holds strings referred to by value0 and value1;
-    bool compound0_, compound1_;
+    bool compound0_ = false, compound1_ = false;
     CharString value0_, value1_;
 };