Tested gender discrimination in response to familiar labels in 75 17-42 mo old children. A pretest employing pictures of familiar objects was presented to ensure that Ss could perform a discrimination task, followed by separate gender tests of photographs of stereotypically masculine and feminine children and adults. There were no sex differences in performance for the gender tests, but among the youngest Ss, more boys than girls could not be tested. Psychometric aspects of the tests were investigated and found adequate. The tests allow individual children to be classified as to gender-labeling ability and provide a useful tool for investigating gender knowledge.