Administered a cognitive test battery that emphasized spatial ability, verbal fluency, and perceptual speed and accuracy to 17 females (aged 12.7-23.2 yrs) and 8 males (aged 13-19.9 yrs) with congenital adrenal hyperplasia (CAH) and 13 normal female relatives (aged 11.4-31.1 yrs) and 14 unaffected male relatives (aged 12.5-28.8 yrs). In addition, 13 fathers and 15 mothers of CAH patients participated. Ss also completed the Progressive Matrices, a vocabulary test, and an early life activities questionnaire (ELAQ). Findings indicate that CAH females, as compared with normal females, showed significantly enhanced performance on hidden pattern, card rotation, and mental rotation tests of spatial ability. On the ELAQ, CAH females, relative to normal females, showed significantly lower frequencies of participation in activities involving verbal expression and a trend toward greater participation in spatial manipulation activities. However, differences between CAH females and normal females in early childhood activities did not account for observed differences in spatial ability, given the absence of a significant correlation between the spatial manipulation activity scale and spatial ability. There was an absence of reliable differences between male CAH patients and controls across spatial tasks. Results are consistent with an effect of pre- and perinatal androgenizing hormones on the development of spatial ability.