diff --git a/icu4c/source/i18n/decimfmt.cpp b/icu4c/source/i18n/decimfmt.cpp
index 59cd6c627f5..407b59eeb8d 100644
--- a/icu4c/source/i18n/decimfmt.cpp
+++ b/icu4c/source/i18n/decimfmt.cpp
@@ -2016,7 +2016,7 @@ void DecimalFormat::setRoundingIncrement(double newValue) {
  * @see #getRoundingIncrement
  * @see #setRoundingMode
  */
-DecimalFormat::ERoundingMode DecimalFormat::getRoundingMode() {
+DecimalFormat::ERoundingMode DecimalFormat::getRoundingMode() const {
     return fRoundingMode;
 }
 
diff --git a/icu4c/source/i18n/unicode/decimfmt.h b/icu4c/source/i18n/unicode/decimfmt.h
index 99b21b9fc50..1509c1f85e1 100644
--- a/icu4c/source/i18n/unicode/decimfmt.h
+++ b/icu4c/source/i18n/unicode/decimfmt.h
@@ -1029,7 +1029,7 @@ public:
      * @see #setRoundingMode
      * @stable ICU 2.0
      */
-    virtual ERoundingMode getRoundingMode(void);
+    virtual ERoundingMode getRoundingMode(void) const;
 
     /**
      * Set the rounding mode.  This has no effect unless the rounding