In vitro and in vivo experiments in closed containers (method of Philips et al., 1980) were conducted to estimate the influence of different temperatures (16, 20, 24, 28 and 32 C) on the attachment and development of a mixed population of Pasteuria penetrans on Meloidogyne incognita - race 1. The greatest attachment rate of endospores of P. penetrans occurred in second-stage juveniles at 28-32C. The bacterium developed at a greater speed within its host at 24, 28 and 32 C than at 20C. Mature sporangium was the predominant life stage observed after 36, 48, 84 and 120 days at 32, 28, 24 and 20C, respectively. The body width and lenght of M. incognita females infected with P. penetrans were smaller initially than the respective dimensions in the uninfected females, but became considerably larger over time at 24, 28 and 32C. At temperatures of 20, 24, 28 and 32C, the average number of endospores per root system was 12,5x10, 27,4x10, and 11,3x10, respectively.