diff --git a/icu4c/source/i18n/numparse_validators.cpp b/icu4c/source/i18n/numparse_validators.cpp
index 12d3465c4ef..98637eeca02 100644
--- a/icu4c/source/i18n/numparse_validators.cpp
+++ b/icu4c/source/i18n/numparse_validators.cpp
@@ -46,8 +46,9 @@ RequireDecimalSeparatorValidator::RequireDecimalSeparatorValidator(bool patternH
 }
 
 void RequireDecimalSeparatorValidator::postProcess(ParsedNumber& result) const {
+    bool parseIsInfNaN = 0 != (result.flags & FLAG_INFINITY) || 0 != (result.flags & FLAG_NAN);
     bool parseHasDecimalSeparator = 0 != (result.flags & FLAG_HAS_DECIMAL_SEPARATOR);
-    if (parseHasDecimalSeparator != fPatternHasDecimalSeparator) {
+    if (!parseIsInfNaN && parseHasDecimalSeparator != fPatternHasDecimalSeparator) {
         result.flags |= FLAG_FAIL;
     }
 }
diff --git a/icu4c/source/test/intltest/numfmtst.cpp b/icu4c/source/test/intltest/numfmtst.cpp
index c855e3e2927..2c54a696c48 100644
--- a/icu4c/source/test/intltest/numfmtst.cpp
+++ b/icu4c/source/test/intltest/numfmtst.cpp
@@ -227,6 +227,7 @@ void NumberFormatTest::runIndexedTest( int32_t index, UBool exec, const char* &n
   TESTCASE_AUTO(Test11649_DecFmtCurrencies);
   TESTCASE_AUTO(Test13148_ParseGroupingSeparators);
   TESTCASE_AUTO(Test12753_PatternDecimalPoint);
+  TESTCASE_AUTO(Test22303_PatternDecimalPoint_InfNaN);
   TESTCASE_AUTO(Test11647_PatternCurrencySymbols);
   TESTCASE_AUTO(Test11913_BigDecimal);
   TESTCASE_AUTO(Test11020_RoundingInScientificNotation);
@@ -9423,9 +9424,26 @@ void NumberFormatTest::Test12753_PatternDecimalPoint() {
     df.parse(u"123",result, status);
     assertEquals("Parsing integer succeeded even though setDecimalPatternMatchRequired was set",
                  U_INVALID_FORMAT_ERROR, status);
-    }
+}
 
- void NumberFormatTest::Test11647_PatternCurrencySymbols() {
+void NumberFormatTest::Test22303_PatternDecimalPoint_InfNaN() {
+    UErrorCode status = U_ZERO_ERROR;
+    DecimalFormatSymbols symbols(Locale::getUS(), status);
+    symbols.setSymbol(DecimalFormatSymbols::kInfinitySymbol, u"infinity", false);
+    symbols.setSymbol(DecimalFormatSymbols::kNaNSymbol, u"notanumber", false);
+    DecimalFormat df(u"0.00", symbols, status);
+    if (!assertSuccess("", status)) return;
+    df.setDecimalPatternMatchRequired(true);
+    Formattable result;
+    df.parse(u"infinity", result, status);
+    assertEquals("Should parse to +INF even though decimal is required", INFINITY, result.getDouble());
+    df.parse(u"notanumber", result, status);
+    assertEquals("Should parse to NaN even though decimal is required", NAN, result.getDouble());
+    df.parse("-infinity", result, status);
+    assertEquals("Should parse to -INF even though decimal is required", -INFINITY, result.getDouble());
+}
+
+void NumberFormatTest::Test11647_PatternCurrencySymbols() {
     UErrorCode status = U_ZERO_ERROR;
     DecimalFormat df(status);
     df.applyPattern(u"¤¤¤¤#", status);
diff --git a/icu4c/source/test/intltest/numfmtst.h b/icu4c/source/test/intltest/numfmtst.h
index 10dd3386d4c..634536fff7c 100644
--- a/icu4c/source/test/intltest/numfmtst.h
+++ b/icu4c/source/test/intltest/numfmtst.h
@@ -283,6 +283,7 @@ class NumberFormatTest: public CalendarTimeZoneTest {
     void Test11649_DecFmtCurrencies();
     void Test13148_ParseGroupingSeparators();
     void Test12753_PatternDecimalPoint();
+    void Test22303_PatternDecimalPoint_InfNaN();
     void Test11647_PatternCurrencySymbols();
     void Test11913_BigDecimal();
     void Test11020_RoundingInScientificNotation();
diff --git a/icu4j/main/common_tests/src/test/java/com/ibm/icu/dev/test/format/NumberFormatTest.java b/icu4j/main/common_tests/src/test/java/com/ibm/icu/dev/test/format/NumberFormatTest.java
index 606afb45cc5..8b61dadc405 100644
--- a/icu4j/main/common_tests/src/test/java/com/ibm/icu/dev/test/format/NumberFormatTest.java
+++ b/icu4j/main/common_tests/src/test/java/com/ibm/icu/dev/test/format/NumberFormatTest.java
@@ -5511,6 +5511,22 @@ public class NumberFormatTest extends CoreTestFmwk {
         }
     }
 
+    @Test
+    public void Test22303() throws ParseException {
+        ULocale locale = new ULocale("en-US");
+        DecimalFormatSymbols symbols = DecimalFormatSymbols.getInstance(locale);
+        symbols.setInfinity("infinity");
+        symbols.setNaN("notanumber");
+        DecimalFormat df = new DecimalFormat("0.00", symbols);
+        df.setDecimalPatternMatchRequired(true);
+        Number result = df.parse("infinity");
+        assertEquals("Should parse to +INF even though decimal is required", Double.POSITIVE_INFINITY, result);
+        result = df.parse("notanumber");
+        assertEquals("Should parse to NaN even though decimal is required", Double.NaN, result);
+        result = df.parse("-infinity");
+        assertEquals("Should parse to -INF even though decimal is required", Double.NEGATIVE_INFINITY, result);
+    }
+
     @Test
     public void Test12962() {
         String pat = "**0.00";
diff --git a/icu4j/main/core/src/main/java/com/ibm/icu/impl/number/parse/RequireDecimalSeparatorValidator.java b/icu4j/main/core/src/main/java/com/ibm/icu/impl/number/parse/RequireDecimalSeparatorValidator.java
index d9301b25209..13c8ed921c5 100644
--- a/icu4j/main/core/src/main/java/com/ibm/icu/impl/number/parse/RequireDecimalSeparatorValidator.java
+++ b/icu4j/main/core/src/main/java/com/ibm/icu/impl/number/parse/RequireDecimalSeparatorValidator.java
@@ -23,8 +23,9 @@ public class RequireDecimalSeparatorValidator extends ValidationMatcher {
 
     @Override
     public void postProcess(ParsedNumber result) {
+        boolean parseIsInfNaN = 0 != (result.flags & ParsedNumber.FLAG_INFINITY) || 0 != (result.flags & ParsedNumber.FLAG_NAN);
         boolean parseHasDecimalSeparator = 0 != (result.flags & ParsedNumber.FLAG_HAS_DECIMAL_SEPARATOR);
-        if (parseHasDecimalSeparator != patternHasDecimalSeparator) {
+        if (!parseIsInfNaN && parseHasDecimalSeparator != patternHasDecimalSeparator) {
             result.flags |= ParsedNumber.FLAG_FAIL;
         }
     }