Some aspects of the reproductive biology of the Lethrinus lentjan (Lacepède, 1802), in Yemen coastal water of the Red Sea were studied from April 2003 to March 2004. Five maturity stages were described for gonad development based on external features. Following the monthly changes of different maturity stages, as well as gonadosomatic indices the spawninmg season extended from March to June with a peak in April-May. Sexual maturation in female started at about 170 mm and the size at which 50% of females mature was determined as 185mm, being completed at 260mm. Sizerelated discrepancy in female to male sex ratio was observed where females generally predominated in the smaller sizes and males in the larger sizes.The total fecundity ranged from 80295 for 192 mm TL female to 837251 for 400 mm female.