RESUMEN
Cajamarca is an important Andean livestock production area located in northern Peru and at the same time endemic in a poorly studied disease known as paramphistomosis. The purpose of this research was to calculate the frequency of paramphistomids in sheep (Ovis aries) slaughtered in the Camal Municipal de Cajamarca, located in the city of Cajamarca. Between the months of February to September 2019, 386 samples of rumen-reticulum were collected that were later classified by age and origin of the animals. Transferred to the laboratory, the stomach contents were emptied; they were examined meticulously and exhaustively in order to find, collect and recognize the parasites adhering to the walls of the compartments. Nineteen samples were positive for Calicophoron microbothrioides in the rumen and none in the reticulum, thus obtaining a frequency of 4.92% in the presentation of paramphistomids in the sampled sheep. According to the origin, the town of Chanta presented a higher frequency with 9.09% and Bambamarca had the lowest frequency with 2.86%. In the age groups, sheep from 2 to 2.5 years old showed a 5.76% presence of paramphistomids and 3.33% of those 4 years old and older were positive. Pearson's correlation coefficient (r = -0.25473762) indicates that there is a low and inversely proportional negative relationship between age and frequency. Finally, with the Chi-square test, no significant difference was obtained between the place of origin and the number of positive cases.