Dermatophytosis is a disease that affects the stratum corneum of the skin, hair and nails in Guinea pigs, causing bad aspect of the carcass, affecting its commercialization and generating economic losses. For the study 189 samples of Guinea pigs with dermatological lesions were collected in intensive breeding farms; the Guinea pigs were analyzed by cytopathology and mycological culture in the Laboratory of Microbiology and Microscopy of Universidad Científica del Sur. The frecuency of dermatophytosis was 18.5 ± 5.5 % by mycological culture and 43 ± 7.1 % by cytopathology; according to the age stratum, the dermatophytosis frecuency was 0 % / 0 % in breeding, 25.6 % / 62 % in rearing, and 4.8 % / 6 % in reproductive Guinea pigs by mycological culture and cytopathology, respectively. About the location of the lessions, a frequency of 0 % / 0 % was found in cages by both techniques, while...