The main technical parameters of four improved guinea pig genotypes currently available and subjected to two feeding systems (mixed and integral) during the growth stage were evaluated. Ninety-six newly weaned male guinea pigs (15 ± 3 days) belonging to the genotypes: Cieneguilla-UNALM, Peru-INIA, Cuy G-IVITA/Mantaro/UNMSM, and Inkacuy-UCSS were used. Pelletized diets as well as water, were offered ad libitum for eight weeks, while forage (maize husks) was only supplied to the mixed treatments. A completely randomized design with a factorial arrangement of eight treatments and three replicates of four animals in each was used. The factors were the genotype on the one hand, and the feeding system (mixed and integral) on the other hand. The results showed that, at the genotype level, Cieneguilla, Cuy G and Inkacuy recorded better weights and weight gains (p < 0.05) compared to Perú. Feed conversion favored (p < 0.05) the T2 treatment (Cieneguilla-integral); in general, the Cieneguilla-UNALM genotype performed better than the others; meanwhile, the systems with and without forage, except for intake that was higher in the first (p < 0.05), showed a similar behavior (p > 0.05).