Objective: This study investigated the difference of attention problems between the subtypes of Attention-Deficit /Hyperactivity Disorder (ADHD) from a neuropsychological perspective. Methods: Participants were grouped by diagnosis: 31ADHD-C (combined type) and 31ADHD-I (inattentive type). There were no significant differences in age, IQ scores, and social economic status between subtypes. Each participant received a neuropsychological examination and was administered the comprehensive non-verbal attention test battery (CNAT). Results: The ADHD-C and ADHD-I groups showed different error patterns in every subtest as compared to normative data. A further analysis of the subtests' reaction times with 75% accuracy rates found that only the ADHD-C group showed deficit in the principle reverse task. When compared to the ADHD-I group, the ADHD-C group showed more impulse errors, missing errors, commission errors and a significantly longer reaction time in many of the subtests. However, the ADHD-I group had significantly more delayed errors in the searching task than the ADHD-C group. Conclusion: The results indicated that with average IQ score, the ADHD-C group had more deficits than the ADHD-I group in several attention components, including sensory selection, sustained attention, attention resource, and response selection based on Cohen's attention model. While the ADHD-I group had deficits in sustain attention and response selection. These findings would be helpful in designing individualized cognitive rehabilitation programs for the two ADHD subtypes.