The study evaluated the performance of Tris-egg yolk and Citrate-egg-yolk as extenders for freezing ram semen in straws and the integrity of sperm membrane of frozen sperm at the National Semen Bank-UNALM, Lima, Peru using six ram semen donors of three breeds. The semen was collected in an artificial vagina, diluted with Tris-glucose-quail egg yolk (Tris) or with Citrate-glucose-egg yolk (Citrate), stored in 0.5 ml pellets, and frozen in liquid nitrogen. Thawing was done at 38 °C for 15 seconds. In refrigerated semen, the Progressive Individual Motility (PIM) in diluted semen with Tris was 82.3% and with Citrate was 79.2%, and the integrity of the cytoplasmic membrane (HOST) was 78.0 ± 4.4 with Tris and 73.2 ± 5.8% with Citrate. In thawed semen, PIM was 62.0 and 56.8%, and HOST was 49.8 ± 3.9 and 41.3 ± 3.8% for Tris and Citrate respectively, with significant differences between extenders, rams and processing period (p<0.01). There were significant lineal regressions (p<0.001) between PIM of refrigerated semen and HOST after thawing for both extenders. It was concluded that Tris showed better performance than Citrate for freezing ram semen, and the hipoosmotic swelling test allowed to show differences between extenders, rams and processing periods.