Reproductive capacities of two braconid wasps, Apanteles subandinus and Orgilus lepidus, endoparasitoids of larval potato tuber moth (PTM), Phthorimaea operculella (Lepidoptera: Gelechiidae)were investigated. The results showed following advantages of the two parasitoids when their reproductive capacity was compared: 1) The realised fecundity of O. lepidus is higher than A. subandinus when they expose to various densities of PTM at 24oC; 2) female O. lepidus has a greater number of ovarioles that allow it to produce more eggs than A. subandinus; 3) in both species, there is essentially no preoviposition period; 4) female O. lepidus does not decrease in size in laboratory, but A. subandinus becomes smaller when kept in continuously laboratory culture, perhaps due to inbreeding; 4) fecundity of female A. subandinus is higher than O. lepidus at high temperature; 5) A. subandinus has the advantages of shorter developmental time and more generations per annum than O. lepidus; 6) both species have greater fecundity than their host. The results indicate that these species should cause complementary mortality of PTM and thereby increase the degree of biological control than either species alone.