In this paper, the histopathological aspects of plague infection in different species of wild and domestic rodents (cricetidae, echymidae, muridae and cavidae) are described. All of them had been trapped in endemic plague areas and harboured natural infection, while others were laboratory infected by different routes (percutaneous, subcutaneous rout, fleas bite). Several national and foreign strains of Yersinia pestis have been studied. All the rodents, except the group of cavidae, had a bubosepticemic plague. From all the lesions described, liver multifocal coagulative necrosis, diffuse acute interstitial pneumonia and lymphoid atrophy of the spleen were the most frequent and so can be considered, for practical purposes, as histological indicators of plague infection, although they are not exclusively found in plague. The variety and intensiveness of lesions found in Zigodontomys L. pixuna, may explain the high mortality of this species of rodents, making easier the dissemination of plague in the natural foci of northeast Brazil. Similar histological lesions were detected in cricetidae and muridae. The resistance of cavidae to plague infection has become evident, since they survived to the acute phase of infection and developped an intensive histiocytic granulomatous reaction surrounding necrotic areas (abscesses). It is suggested thad these chronic lesions may harbour virulent bacilli and so explain periodic plague infection in local fleas, leading to reactivation of epizootics.