Event-related potentials (ERPs) were recorded from 6-month-olds as each watched pictures of the mother's face and a stranger's face. The ERPs differed for the 2 faces, but the pattern of neural activity elicited depended on whether the mother and stranger looked different (Experiment I, n= 22) or alike (Experiment 3, n= 22). In contrast, when different 6-month-olds were each shown 1 of these 44 pairs, of face their ERPs did not differ between the 2 faces (Experiment 2, n= 22, and Experiment4, n= 22). In a visual preference test of recognition, infants showed no evidence of recognizing the mother's face (Experiment 5, n= 32). Together, these results suggest that infants are able to recognize their mothers' faces but (1) the neural processes accompanying recognition depend on the difficulty with which mother can be discriminated from stranger and (2) under the conditions investigated in this study, FRPs are a more sensitive measure of recognition than is looking time.