An abnormal female infant, who survived for 10 months with almost complete trisomy 16p and monosomy of sub-band 21q22.3, is described. The chromosome anomaly was the result of an unbalanced segregation of a maternal balanced translocation t(16;21)(p11;q22.3). The partial monosomy was considered to have had little or no adverse phenotypic effect. Cases with trisomy of chromosome 16 material are reviewed. It appears that while full trisomy 16 always results in early spontaneous abortion, trisomy 16p or 16q may be compatible with limited postnatal survival.