The potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) (PTM) is the most destructive pest. One of the most successful groups of biological control agents against soil insect pests are the entomopathogenic nematodes (EPNs) in the families Steinernematidae and Heterorhabditidae. This study assessed the effects of EPNs (Nematoda: Steinernematidae) species [Steinernema feltiae (Balıkesir isolates) and Heterorhabditis bacteriophora (Çanakkale isolates) (Nematoda: Heterorhabditidae)] detected in our country (Turkey) against the larvae and pupae of P. operculella in greenhouse-pot experiments. S. feltiae was the most effective killing 6.33±0.61 (63.30%) larvae, whereas H. bacteriophora only killed 3.67±0.56 (36.70%) dead larvae. 0.17±0.17 (1.70%) larvae died in control group after 10 days and 9.33±0.33 (93.30%) developed into the pupa. For pupal stages, H. bacteriophora was more effective causing 48.30% (4.83±0.60) pupal mortality whereas S. feltiae caused 35.00% (3.5±0.72) mortality. 1.00±0.36 (10.00%) dead pupa was detected at the end of 10 days in the control groups. Although S. feltiae was more effective than H. bacteriophora against potato moth larvae, H. bacteriophora was more effective than S. feltiae in applications against pupae. This research, which is the first study carried out in greenhouse-pot conditions on the use of EPNs in the control of P. operculella in Turkey, shows that more detail studies on the applications of EPNs with promising effects (S.feltiae Balıkesir isolate applications with a 63.30% mortality in larvae) under field conditions be conducted.