Cotton bollworm, Helicoverpa armigera Hubner, is a cosmopolitan polyphagous pest of many crops. Habrobracon hebetor Say and Helicoverpa armigera nucleopolyhedrovirus (HearNPV) are two important biocontrol agents used to manage this pest, sometimes in combination. We evaluated the sublethal effects of HearNPV on H. hebetor life table parameters under laboratory conditions when its host (second instar H. armigera) was treated with HearNPV, and tested H. hebetor females for their ability to discriminate against inoculated hosts. Emergence of adults reared as solitary larvae was reduced by half on LC₃₀-inoculated larvae compared to controls, but not on LC₅ or LC₁₅-inoculated hosts. Low concentrations (LC₅, LC₁₅, and LC₃₀) of HearNPV had no effects on overall parasitoid developmental time, but longevity and lifetime fecundity was reduced for females emerging from hosts receiving the LC₃₀ treatment. Net reproductive rate (R₀), intrinsic rate of increase (rm), and finite rate of increase (λ) were all decreased in a concentration-dependent manner in the LC₁₅ and LC₃₀ treatments, as were female life expectancy, age-specific survivorship (l_x), and age-specific fecundity (m_x), whereas population doubling time (DT) increased. Parasitoids did not discriminate against LC₁₅inoculated larvae in choice or no-choice tests, but parasitized more LC₅₀-inoculated hosts than controls in the choice test, with no significant differences in total numbers of eggs laid in either case. Although parasitoids suffered some loss of fitness in HearNPV-inoculated hosts under these laboratory conditions, these agents still appear compatible for joint application against H. armigera under field conditions, provided parasitoid releases are made 2 d after NPV application.