Age differences in the intensity of emotional expression of infants ages 7 to 8 months were compared to those ages 9 through 13 months. All 82 participants (33 boys, 49 girls) were prescreened for normal development. Participants were each presented with a randomized order of 12 stimuli (peek-a-boo, still face, stranger approaches, toy bug, toy taken, parent leaves, toy switch, puppets, toy out of reach, squeaky toy, jack-in-the-box, and loud noise). Emotional responses were video recorded and analyzed. Intensity of emotional expression was measured on an ordinal scale (PEEX: Parameters of Emotional Expression) incorporating MAX facial codes and vocal and bodily items from Lab-Tab. Coding was analyzed for reliability. Older infants were significantly more intense in their emotional expressions than younger infants.