To evaluate the relationship between soft neurological signs and various proposed dimensions of impulsivity (behavioral and cognitive), 31 boys (6-13 years, mean +/- SD 10.1 +/- 1.8) with disruptive behavior disorders, and 45 age-matched boys without DSM-III-R pathology, were independently assessed on clinical ratings of impulsivity, a battery of cognitive tests intended to score impulsive responding, and a neurological examination for soft signs. After being corrected for age, neurological soft signs correlated positively with impulsive responding on the Matching Familiar Figures Test (inpatients and normals) and the Continuous Performance Test (in normals), but not with IQ or clinical impulsivity rating scores. These findings suggest a relationship between neurological dysfunction/immaturity and performance on specific tasks requiring response inhibition, thus adding value to the cognitive assessment of impulsivity.