The efficiency of proteins of legume forages in ruminant nutrition is poor because of their extensive degradation in the rumen. The objective of this study was to evaluate the variation available for protein degradation in tannin-free (alfalfa and white clover) and tannin-rich (Lotus sp.) legume species. Protein and dry matter degradation were measured by in sacco incubation of forage samples in the rumen of fistulated cows, for 2, 8 or 48 h. Condensed tannin content was measured on Lotus samples. Variation in protein degradation was low among alfalfa and white clover cultivars, but the degradation was more important for alfalfa than for clover cultivars. Protein degradation was less important in Lotus sp. than in alfalfa or clover, and the variation among Lotus cultivars was mainly related to condensed tannin content.