Females of Phyllophaga obsoleta Blanchard (Coleoptera: Melolonthidae) display a typical “calling” behavior by protruding the abdominal tip and exposing their genital chamber. This is the moment when the sex pheromone is released into the environment. The genital chamber and accessory glands have a specialized epithelia involved in production of the chemicals. In other species of the group (e.g., Costelytra zealandica White), bacteria have been confirmed to be involved. We identified the microorganisms in the genital chamber of females of P. obsoleta. Two types of bacterial colonies were isolated from the inside of the genital chamber and identified using the 16S rRNA gene sequence. The sequence of one of the bacterial colonies was a 97% match with the Klebsiella oxytoca strain HP1 sequence, while the sequence of the other bacterial colony was a 98% match with the Klebsiella michiganensis strain VITSW4 sequence. Microbiological and biochemical tests were used for taxonomic identification. Both bacteria produce indole and acetoin, chemicals that have been reported as attractants and sex pheromones in other insects, showing they can potentially participate in production of sex pheromone of P. obsoleta.