INTRODUCTION: The testes are ovoid or walnut shaped bodies suspended in the scrotal region by the support of scrotal tissue including non striated dartos muscle and spermatic cord. MATERIALS AND METHODS: The study was conducted in the Department of Anatomy, Gauhati Medical College, Guwahati on the testis of human, pig, goat and albino rat. They were divided into four mammals group consisting of 6 to 9 animals in each group. RESULTS: Biometrical values were statistically analyzed and signicant differences of length, breadth, thickness and weight were noted. It was found that in all groups, the measurements were more in right side than the left but was found to be statistically insignicant. The highest values in case of length, breadth, thickness and weight were found in pig and lowest in the albino rat. This descending pattern of the biometrical value from pig to human and pig to albino rat to their body weight was highest in pig and lowest in albino rat. The high value in the right side is sup CONCLUSIONS: posed to be due to organogenesis in the right side where it occurs rst during the development. Therefore it needs further evaluation in this matter.