Abstract: The present study aimed to determine the effect of 17α-hydroxyprogesterone (17α-OHP) and 17α-hydroxypregnenolone (17α-OHPL) on sperm quality and sperm quantity in male mud spiny lobster (Panulirus polyphagus). The mean of sperm quality was increased in 17α-OHP and 17α-OHPL treated hormones. In 17α-OHP injected animals, the mean of sperm quantity of dose 0.01 μg g-1 b.wt. was increased than 17α-OHPL. Meanwhile, 17α-OHP and 17α-OHPL concentrations were lower when injected with the hormones but 17α-OHP was higher at only day 15 (dose 0.01 and 0.1 μg g-1 b.wt.). For 17α-OHPL, the hormone was a prohormone in the body of P. polyphagus and only required smaller to increase the sperm quantity. Besides, when the higher dose of 17α-OHPL (0.1 μg g-1 b.wt.) was used in P. polyphagus, the development of P. polyphagus was inhibited and decreased the sperm quantity and 17α-OHPL concentration in hemolymph was lower. Injection of 17α-OHP in P. polyphagus has increased the sperm quality and quantity for both 17α-OHP dosage of 0.01 and 0.1 μg g-1 b.wt. However, injection of 17α-OHPL in P. polyphagus has decreased the sperm quantity only, also for both dosage of 0.01 and 0.1 μg g-1 b.wt. and lower on hormone concentration.