Abstract : We present a family segregating for t(5;9)(p15.1;q34.13). Two cases with der(5), t(5;9), resulting in a partial duplication 9q34.13----qter and partial deletion of 5p15.12----pter, were ascertained. The phenotypes were consistent with features of both the cri du chat and trisomy 9q3 syndromes.