Effect of exogenous methyl farnesoate supplementation on maturation of freshwater prawn Macrobrachium rosenbergii was studied with different doses of methyl farnesoate (0.25, 0.5, 0.75, 1.00 and 1.25ᶙg of MF/20g prawn). The prawns which didn't receive any injection were served as control while the prawns which got an injection of distilled water were regarded as concurrent control. Female prawns of 30±2g and male prawns of 45±2g were reared separately in triplicates for 60 days duration. None of the animals stocked into the tank had gonadal development at the beginning of the experiment. The gonado-somatic index was assessed on the 1st and last day of the experiment. Histology of both ovary and testes were done at the end of the experiment to understand the maturity stages of the prawn. The histological observations revealed the difference among the treatment was only visible in the thickness of the interstitial space as well as the density of spermatids in the tubule. Similarly the female prawns also attained the maturing stage with abundant vitellogenic ova in the follicular as well vitelline membrane. From the experiment it is revealed that, even though all the animals in the experiment reached maturity at the end of 60th day, there were no significant differences between the treatments. Hence it is revealed that methyl farnesoate hormone doesn't have an influence on maturation in sub adults of fresh water prawn.