Entomopathogenic nematodes (EPNs) are successfully used in the biological control of agricultural insect pests. This study aims to determine the body length of hermaphrodite individuals, egg diameter and reproductive capacity obtained from Infective Juveniles (IJs) stored at different temperatures and durations. Heterorhabditis bacteriophora Poinar, 1976 (Rhabditida: Heterorhabditidae)’s Hybrid Strain HBH was used in the study. IJs stored at 15, 25 and 35°C for 7, 14 and 21 days were inoculated onto Galleria mellonella L., 1758 (Lepidoptera: Pyralidae) last instar larvae at a dose of 100 IJs. On the 2nd day of infection, hermaphrodite individuals and eggs were obtained by dissecting the larvae. The reproductive capacity was determined 10-12 days after infection. The study was conducted in Bursa Uludağ University, Faculty of Agriculture, Plant Protection Department, Nematology Laboratory in 2023. In conclusion, the longest hermaphrodite individuals and egg diameter were obtained as 6207.22 µm and 55.65 µm, respectively from the IJs stored for 7 days at 15°C. The highest reproductive capacity was also observed as 167.500 IJs per G. mellonella larva in IJs stored under the same conditions with respect to temperature and time. This study is important for assessing the morphological effects of different temperature values and storage durations on EPNs.