The chromosome set of the lesser kudu, Tragelaphus imberbis, consists of 38 elements in both sexes. In contrast to most other members of the bovid subfamily Tragelaphinae, both the X and the Y chromosomes are compound, having fused with identical autosomes from ancestors presumed to have higher chromosome numbers. From a comparison of the unusual sex chromosomal rearrangements that have occurred in this family, a hypothetical lineage has been derived. This family tree and the details of various banding studies in the lesser kudu are described.