Partial trisomy 6p with duplications ranging from 6p21 to 6p25-pter is emerging as an established syndrome. We report a case of duplication of 6p (6p23-pter) and deletion of 2q37-qter. Features characteristic of 6p partial trisomy present in the patient are low birthweight, and mental and developmental retardation. Major facial features include prominent forehead, flat occiput, multiple ocular abnormalities, low-set ears, prominent nasal bridge, long philtrum and small pointed mouth. Repeated examinations of the patient from birth to the age of over 5 years revealed that he has infantile autism. Since autistic children are generally not associated with chromosome anomalies, in view of the present case, it is suggested that karyotypic analysis be considered for such children. Where possible, extended study for autism in 6p trisomic children may also be desirable.