On the basis of chromosome data obtained on 30 species and 20 subspecies of Cervidae, a report is submitted on the karyosystematics of this family. The primitive karyotype of Cervidae may be inferred to be composed of 35 acrocentric pairs (2n = 70 FN = 70). During the phyletic evolution of this family different types of chromosome rearrangements were probably selected and the group may have differentiated karyologically into three branches: (1) the Cervinae that fixed a centric fusion resulting in a metacentric pair of autosomes (2n = 68, FN = 70), as shown by the basic karyotype of Cervus elaphus, and where Robertsonian fusions are the preeminent type of chromosome rearrangement; (2) the Odocoileinae, in which pericentric inversions and Robertsonian fusions were favored, yielding first a submetacentric X and then a submetacentric autosome pair. The most representative karyotype is 2n = 70, FN = 74--as in Odocoileus hemionus; and (3) the Muntiacinae, in which centric and tandem fusions were the most common chromosome rearrangements. While Muntiacus reevesi has a karyotype 2n = 46, FN = 46, the chromosome number drops down to 2n = 6 in the females of the M. muntjak vaginalis subspecies group and M. rooseveltorum. Therefore, while the karyotypes are conserved within the subfamilies Cervinae and Odocoileinae; the subfamily Muntiacinae appears to be the most chromosomally diversified group. The few karyological data on the Moschus berezovskii suggest that the Moschinae should be placed in a separate family, the Moschidae.