THROUGH work with short-term cultures of leucocytes from peripheral blood according to the phytohaemagglutinin method, the opportunity arose to examine the chromosome complement of the red fox (Vulpes vulpes Lin.). As no description of the chromosome morphology has previously been published, these observations are of some interest. Wodsodalek1 determined the chromosome number at 42, with sex chromosomes of the XY type, while Andres2 found the chromosome number in haploid cells to be 17. In 1947, Makino3 found 38 chromosomes in the spermatogonia of the silver fox and this number was later confirmed by Lande4.