We report on an infant with multiple congenital anomalies possessing a derivative 14 chromosome in excess of the normal complement, resulting from transmission of a familial t(5;14)(p13;q22). The proposita's phenotypically normal mother, mentally retarded half-brother, and fetal sib are carriers of the apparently balanced translocation. Previous cases of similar familial t(5;14) are reviewed. The proposita's phenotype is characterized by failure to thrive, developmental retardation, cleft palate, congenital heart anomaly, abnormal hands and feet, unusual face with abnormal ears, and recurrent respiratory infections. The proposita died at age 9 months and postmortem examination showed multiple central nervous system, cardiopulmonary, gastrointestinal, and genital malformations. Our proposita's phenotype is attributable to contributions from both chromosomes and is consistent with the consequences of both the dup(5p) and dup(14q).