Eight hematological values were determined in blood samples from 88 raptors representing 10 species. 2. Means, standard errors, ranges and coefficients of variations were obtained for each parameter and species investigated. 3. The griffon vulture (Gyps fulvus) showed mean concentrations of glucose lower than those of most of the other species. 4. Concentrations of urea in the buzzard (Buteo buteo) were higher than those of the other raptors studied, and the black kite (Milvus migrans) had cholesterol values greater than the other species. 5. Blood values of individual birds of prey in good and bad states of nutrition were compared, showing significant changes in cholesterol, hematocrit, urea and total protein values.