To establish the relationship between the intensity of the green color of leaves and their crude protein (CP) concentration in Urochloa brizantha, U. decumbens and U. humidicola pastures in the Piedemonte Llanero, Colombia, the leaf chlorophyll concentration was measured (in SPAD units), classified based on the Munsell color chart and compared with the leaf CP concentration determined by the Kjeldahl method. The regression analysis between chlorophyll and CP concentrations showed coefficients of determination (r2) between 0.76 and 0.88. While collection of additional data will allow colorimetric charts based on the Munsell color chart to be developed which can be used to predict CP levels for each of these species, the relationships generated can be used to develop recommendations to assist farmers in the region in their decisions on use and fertilizing of these pastures.