The first chromosomal characteristic of F 1 hybrid catfish from Thailand was studied. Kidney cell samples were taken from four male and four female fish. The mitotic chromosome preparations were done directly from kidney cells. Conventional staining technique was applied to stain the chromosomes. The results showed that the diploid chromosome number of Mekong giant catfish (Pangasianodon gigas) striped catfish (P. hypophthalmus) and spot pangasius (Pangasius larnaudii) P. hypophthalmus were 2n=60, the fundamental number (NF) was 108 in both males and females. The chromosomes presences of metacentric, submetacentric, acrocentric, and telocentric chromosomes were 27-11-10-12 and 25-12-11-12, respectively. While the chromosomes of P. gigas, P. hypophthalmus, and P. larnaudii (parents) presences of metacentric, submetacentric, acrocentric, and telocentric chromosomes were 28-12-12-8, 26-10-8-16, and 24-14-14-8, respectively. Results obtained will increase our basic knowledge of the cytogenetics of the family Pangasiidae which could form the basis for future research and provide data to ensure their survival. The karyotype formulae could be deduced as: × , 2 (60) = 27m +11sm +10a +12t × , 2 (60) = 25m +12sm +11a +12t P. gigas P. hypophthalmus n P.larnaudii P. hypophthalmus n