The chromosome number in gill, intestine and liver tissues of Poecilia velifera and Poecilia latipinna were investigated. Method of chromosome preparation was modified from Kligerman and Bloom (1977). The chromosome number of P. velifera was 2n=34 while chromosome number of P.latipinna varied between 2n=34 to 2n=48. Further studies need to be continued to determine the actual number of chromosome of P. latipinna.