diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/ReturnValueIgnored.java b/core/src/main/java/com/google/errorprone/bugpatterns/ReturnValueIgnored.java
index 19dcf80a9a3..09f3257b353 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/ReturnValueIgnored.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/ReturnValueIgnored.java
@@ -30,6 +30,7 @@
 
 import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
+import com.google.errorprone.ErrorProneFlags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.util.ASTHelpers;
@@ -150,9 +151,7 @@ private static boolean functionalMethod(ExpressionTree tree, VisitorState state)
    * void-returning ones, which won't be checked by AbstractReturnValueIgnored).
    */
   private static final Matcher<ExpressionTree> STRING_METHODS =
-      anyOf(
-          staticMethod().onClass("java.lang.String"),
-          instanceMethod().onExactClass("java.lang.String"));
+      anyMethod().onClass("java.lang.String");
 
   private static final ImmutableSet<String> PRIMITIVE_TYPES =
       ImmutableSet.of(
@@ -209,6 +208,12 @@ private static boolean functionalMethod(ExpressionTree tree, VisitorState state)
           instanceMethod().onExactClass("java.util.Optional").named("isPresent"),
           instanceMethod().onExactClass("java.util.Optional").named("isEmpty"));
 
+  /**
+   * The return values of {@link java.util.concurrent.TimeUnit} methods should always be checked.
+   */
+  private static final Matcher<ExpressionTree> TIME_UNIT_METHODS =
+      anyMethod().onClass("java.util.concurrent.TimeUnit");
+
   private static final String PROTO_MESSAGE = "com.google.protobuf.MessageLite";
 
   /**
@@ -246,8 +251,16 @@ private static boolean functionalMethod(ExpressionTree tree, VisitorState state)
               .namedAnyOf("containsKey", "containsValue")
               .withParameters("java.lang.Object"));
 
+  private final Matcher<? super ExpressionTree> matcher;
+
+  public ReturnValueIgnored(ErrorProneFlags flags) {
+    boolean checkTimeUnit = flags.getBoolean("ReturnValueIgnored:TimeUnit").orElse(true);
+    this.matcher =
+        checkTimeUnit ? anyOf(SPECIALIZED_MATCHER, TIME_UNIT_METHODS) : SPECIALIZED_MATCHER;
+  }
+
   @Override
   public Matcher<? super ExpressionTree> specializedMatcher() {
-    return SPECIALIZED_MATCHER;
+    return matcher;
   }
 }
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/ReturnValueIgnoredTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/ReturnValueIgnoredTest.java
index 42294cf5940..43eeadcbb0d 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/ReturnValueIgnoredTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/ReturnValueIgnoredTest.java
@@ -177,6 +177,22 @@ public void optionalInstanceMethods() {
         .doTest();
   }
 
+  @Test
+  public void timeUnitApis() {
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            "import static java.util.concurrent.TimeUnit.MILLISECONDS;",
+            "class Test {",
+            "  void timeUnit() {",
+            "    long ms = 4200;",
+            "    // BUG: Diagnostic contains: ReturnValueIgnored",
+            "    MILLISECONDS.toNanos(ms);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
   @Test
   public void issue1565_enumDeclaration() {
     compilationHelper