The nutritive value of evening primrose (Oenothera paradoxa) oil cake was estimated from chemical composition and nutrient digestibility. The cake contained on average (per kg): 210 g crude protein, 0.55 UFL, 0.44 UFV, 110 PDI (PDIE - PDIN = - 22 g), 92 g PDIA and 100 g of ether extract. The proportion of methionine and cystine in cake was relatively high (1.97 and 2.17 g/16 g N) but that of lysine was rather low (2.00 g/16 g N). Linoleic (C_{18:2 n-6}) - 73.1%, γ-linolenic (C_{18:3 n-6}) - 9,0% and oleic (C_{18:1 n-9}) - 6.4% acids dominated in total fatty acid content. Rumen degradability and intestinal digestion coefficients of protein of evening primrose oil cake or seeds were 0.39 and 0.65, respectively.