Abstract: The entomopathogenic bacterium, Photorhabdus luminescens and its metabolites were found lethal to the Galleria mellonella when applied in sand media. Bacterium penetrated quickly in the haemocoele as it got contact with insect body. It was also observed that the toxic metabolites caused more larval death than the bacterial cells. P. luminescens cells were recovered from the haemocoele when suspensions containing bacterial cells were applied to the G. mellonella indicating that bacterial symbionts do have a free-living existence and can enter the haemocoele in the absence of nematode vector. This bacterium or its toxic secretions can be used for insect control that can be important component of integrated pest management against different insect pests.