The subjects were drawn from a perinatal cohort consisting of all children born between September 1, 1959, and December 31, 1961, at a hospital in Copenhagen. The sample included 36 boys with schizophrenic mothers or fathers, 36 with psychopathic fathers or character-disorder mothers, and 57 whose parents had never had a psychiatric hospitalization. The degree of sinistrality was determined in 1972 through a questionnaire and through a neurological examination; and left-handedness, left-footedness, eye dominance, and familial left-handedness were considered. Also measured were intelligence, motor impairment, and social interaction. An examination of the record of offenses in the Danish national police register in 1978 served as a source for the measure of delinquency. A multivariate analysis of variance demonstrated that offenders tended to be sinistral, and a univariate analysis of variance showed that eye dominance was the only measure of sinistrality which was not significantly related to delinquency. The neurologist's judgement of left-handedness proved to be more accurate than the questionnaire in predicting delinquency. Of the 17 boys he selected as definitely left-handed, 64.7 percent were later arrested at least one time. Only 29.5 percent ofthe right-handed group were later arrested. When compared with the other variables of parent deviance and familial lefthandedness, the subjects' handedness remained the only variable significantly related to delinquency. In a search for mediators in the relationship between sinistrality and delinquency, verbal intelligence, neurological impairment, and social interaction scores were considered. None of these factors correlated with delinquency or with hand preference. However, the explanation for the relationship may be associated with the fact that left-handers generally do not have the pronounced left-hemisphere cerebral dominance of right-handers. Related literature is reviewed. Data tables, footnotes, and approximately 30 references are included.