Abstract: The authors have for the time observed that somatic cell of Cathaya argyrophylla contains 24 chromosomes (2n=24) (plate I, 3). One pair of them are subtelocentric chromosomes and the rest are metacentric or submetacentric (Fig. 1). This shows that Cathaya is similar to most of genera in Pinaceae in chromosome numbers, but different from Pseutotsuga (2n-26). It seems that Cathaya is not closely related to Pseudot-suga, although its wood anatomy is very similar to that of Pseudotsuga.