Six patients (4 females and 2 males) with terminal deletion of the short arm of chromosome 9 distal to band p22 are described. The disorder constitutes a clinically identifiable syndrome consisting of mental retardation, sociable personality, trigonocephaly, mongoloid eyes, wide flat nasal bridge, anteverted nostrils, long upper lip, short neck, long digits mostly secondary to long middle phalanges, and predominance of whorls on fingers. The findings suggest that the clinical features are antithetical to the trisomy 9p syndrome. The deleted chromosome segment is relatively small and could be easily overlooked. It is hoped that this delineation of clinical features seen in 9p- patients may help in focusing attention on the small deletion.