There is a definite pattern of the growth of seminiferous tubules at different post natal ages in mammals. The present work involves recording the changes of the seminiferous tubules, the cellular components of the seminiferous epithelium and the Leydig cells in male Assam goats. Different micrometrical parameters of the seminiferous tubules were found to increase with the increase in age of the male goats and they showed a significant (P < .05) increase between the age of 6 and 8 months. Also, the micrometrical parameters of different spermatogenic cells showed a significant (P < .05) increase between 6- and 8-month-old goats. The Leydig cells could be marked in the intertubular tissue right from birth. Various micrometrical parameters of the Leydig cells were found to increase with the advancement of age of the male goats. The nuclear diameter of the Leydig cells did not show a definite pattern during their postnatal growth. The other micrometrical measurements of the Leydig cells denoted their highest values at the age of 8 months.