The developmental changes of the rabbit mesonephros during the prenatal life were studied in 31 rabbits at embryonic days (E) 10-24 for light microscopical investigation. Generally, the mesonephros consists of mesonephric duct, tubules and glomeruli. At E 10, the mesonephros includes the mesonephric duct and tubules only as the glomerulus appears at E 11 where, the mesonephric corpuscles show different stages of development. At E 14&15, the mesonephros reaches its maximum size, degree of differentiation and function where, the cells of the secretory tubules show intense P.A.S. activity at their luminal border. The rabbit mesonephros begins to degenerate at E 16 while, the metanephros is early developed at this age and so, they are not overlapped in capability of function. Disappearance of the mesonephros starts at E 20 and it could not be observed at E 24. In conclusion, the rabbit mesonephros is large, present in fully developed state for about 4 days (from 13 to 16 days of gestation) and begins its degeneration early at E 16.