The aim of the study was to determine the frequency of major pathologic lesions in internal organs of guinea pigs infected with Salmonella spp. The retrospective study was conducted using 81 necropsy records from the Pathology Laboratory of the College of Veterinary Medicine, San Marcos University, which had positive bacteriological diagnosis to Salmonella spp in the period 2001-2007. Pathological lesions were classified in inflammatory processes, circulatory disorders, degenerative and adaptive, where inflammation was the most common pathological disorder (177/408). The results showed a median of five affected organs per animal, the liver being the organ with highest frequency of pathological lesions (87.7 ± 0.1%), and the prevailing pathomorphological image was necrotic hepatitis (36/81).