Three groups of twelve subjects each, ages four, five and six years, respectively, made same-different judgments on six speech discrimination tests. On each test, a single acoustic cue signaled a phonemic difference in minimal pairs which were otherwise acoustically identical. On three of the tests, the independent variable was a spectral cue and on three others a temporal cue was manipulated. With one exception, all subjects passed tests involving a spectral cue, however, significant developmental differences were apparent on tests in which a temporal cue signaled a phonemic difference. The probable contribution of these cues to the perception of speech in young children is discussed.