The purpose of the present study was to examine whether attention deficits contribute to dysfunctional facial emotion recognition in boys with ADHD. The first hypothesis was that ADHD patients would commit more errors in facial emotion recognition than the control group. The second hypothesis was that attention deficits, which were measured by a computerized continuous performance test (CPT), would be responsible for the errors in facial emotion recognition in boys with ADHD. A revised emotional recognition test (ERT) was used to assess the subjects' ability to recognize emotions. The ADHD diagnostic system (ADS), a computerized continuous performance test (CPT), was used to evaluate attention performance. Subjects with ADHD showed significantly lower scores of contextual understanding than the controls (t=-2.569, df=67, P=0.012). Among age, IQ, and ADS scores, only the score of omission errors on the ADS accounted significantly for the score of contextual understanding in ADHD (effect size 3.4%, P<0.05). Attention deficits in boys with ADHD seemed to account for their difficulty in recognizing facial expressions of emotion. Effective treatment for attention deficits is expected to have a beneficial effect on facial emotion recognition in boys with ADHD.