Study on reproductive biology of vermiculated sailfin catfish Pterygoplichthys disjunctinrs (Weber, 1991) in the Mekong delta was carried out from April, 2013 to March, 2014. The results showed that the matured fish in stage IV and stage V was found in all year round, in which the highest ratio of maturation was determined in the period of April-September. Gonadosomatic Indexs (GSD of males were lower than those of females, and GSI of female was high in the period of April-September and the highest value was in June Q.98%). Meanwhile, Hepatosomatic Index (HSD was changed inversely with GSI and ranged from 0.78 to 1.47c/o. T\e condition factor (CF) ranged from 3.08% to 7.2% and showed that CF was higher from April to September. The results indicated that the main spawning season of P. disjunctivus occurred from April to September, however this species can breed in all year round. The fecundity of P. disjunctivus ranged from 252 to 5820 eggs/female and relative fecundity fluctuated from 2665 to 18092 eggs/kg of female. l,ength at first maturity (L.) was 17.12 cm and 9.14 cm of of female and male, respectively.