A field experiment was conducted at the Corozal Experiment Substation in the humid mountain region of Puerto Rico to evaluate the production and persistence of tropical grasses, Brachiaria humidicula, Cynodon dactylon cv. Bermuda, C. nlemfuensis var. nlemfuensis cv. Star, Digitaria pentzii cv. Slenderstem, D. decumbens cv. Transvala, C. plectostachyus cv. Star and Panicum maximum cv. Makueni in small plots grazed at 5- to 7-week intervals for 2 years. P. maximum cv. Makueni was the most productive grass the first year, with a mean of 1.71 ton/ha dry forage per grazing period, but it was not statistically different (P = 0.05) from B. humidicola and C. dactylon cv. Bermuda. D. pentzii was the least productive. Production of all grasses, except P. maximum cv. Makueni, decreased during the short cool days in December and January. B. humidicola was the most productive grass the second year, with a mean of 1.73 ton/ha of dry forage, followed very closely by P. maximum cv. Makueni. Again D. pentzii cv. Slenderstem was one of the least productive, and C. nlemfuensis did not persist. Mean production of all grasses decreased during the drier periods; however, the crude protein content was higher. Total annual forage production was similar in both years, with means of 15.8 and 15.1 ton/ha dry forage, but much lower than the reported yields of these cultivars under cutting management in Puerto Rico.