Abstract: The study on eleven characteristics including head, bill, body, wattle, wing, tail and tarsus of hill Mynahs from different populations inhabited throughout Thailand discriminated birds into five groups: Northern, Modified Northern, Intermediate, Modified Southern and Southern. Specifically, there were five characters of the yellow connection between the anterior and posterior wattles. The differences among the averages of these characteristics of five different groups were statistically significant. On the other hand the karyological study did not show any correlation between phenotypic variation and genetic divergence in chromosomal aspect. There was no geographical difference in karyotypes. The sizes and shapes of five different hill Mynah group chromosomes were similar. The diploid chromosome number (2n) was 80: ten pairs of macrochromosomes and thirty pairs of microchromosomes. There was a karyotypical invariance among various morphological populations of hill Mynahs from different areas in this study. Eventually, the role of microchromosomes or further study of DNA level is implicated.