Pesq. Vet. Bras. 33(Supl.1):1-7, dezembro 2013 1 semanas de idade (N=5/grupo). Os aspectos analisados incluíram a contagem das populações celulares presentes no estádio 1 do ciclo do epitélio seminífero (CES), eficiên-cia das mitoses espermatogoniais (RMi), produção meió-tica (RMe), rendimento geral da espermatogênese (RGE), índice de células de Sertoli (ICS) e capacidade de suporte das células de Sertoli (CSCS). Os resultados mostraram que número médio de espermatogônias A, espermatócitos primários em pré-leptóteno/leptóteno, espermatócitos primários em paquíteno, células espermatogênicas totais e células de Sertoli mostraram variações numéricas em funAnálise morfológica e funcional do processo espermatogênico em cobaios (Cavia porcellus) da pré-puberdade até a pós-puberdade This study describes the morphological and functional analysis of spermatogenesis in guinea pigs (Cavia porcellus) with five (W5), six (W6), nine (W9) and eleven (W11) weeks of age (n=5/group). The aspects analyzed include counts of cell populations present in stage 1 of seminiferous epithelium cycle (SEC), efficiency of spermatogonial mitosis (EMi), meiotic production (EMe), overall yield of spermatogenesis (EOS), Sertoli cell index (SCI) and carrying capacity of Sertoli cells (CCSC). The results showed that the average number of spermatogonia type A, primary spermatocytes in pré-leptóteno/leptóteno, primary spermatocytes in pachytene, total spermatogenic cells and Sertoli cells showed numerical variations according to age; however they were statistically not detected, while round spermatids increased significantly at puberty and then stabilized. The spermatogenic production of 5 to 11-week-old guinea pigs did not reach the stabilization point, and the RMi, RME, EOS, SCI and CCSC showed significant number variation as a function of age. The results demonstrate that Cavia porcellus in post-pubertal stage 2 are an advantageous experimental model to address studies on the processes of homologous recognition, alignment, and synapsis during meiotic prophase; intrinsic yield of spermatogenesis in guinea pigs is similar to Wistar rats, paca and agouti (Dasyprocta sp.) and lower than in cavies, whereas the functional efficiency of Sertoli cells is higher than in agouti and Wistar rats, and lower than in pacas, spiny rat and collared peccaries. We conclude that in guinea pigs the spermatogenesis is fully established at 6 weeks of age, indicating the pubertal stage of sexual development, and until week 11 they do not reach the maximum daily sperm production and therefore sexual maturity. RESUMO.-Este estudo descreveu as análises morfológica e funcional do processo espermatogênico em cobaios (Cavia porcellus) de cinco (S5); seis (S6); nove (S9) e onze (S11)