Millo blanco (MB), Sorghum bicolor (L.) Moench, and two F1 hybrids (Redlan x MB and CK-60 x MB) were compared for yields of green forage (GF), dry forage (DF), crude protein (CP) content, CP yield, and height at Isabela, Puerto Rico. Six cuttings were made, the first, 58 days after planting and the remaining five, approximately every 30 days. The first harvest produced the highest forage yields. Dry forage yields (DFY) of 7,700 kg/ha produced by CK-60 x MB were 27.3% more than those of the male parent. The CP content of the three genotypes 58 days after planting was about 16% and crude protein yield (GPY) of 1,362 kg/ha was observed on CK-60 x MB, 33% more than that of MB. Although forage yields of the three genotypes were reduced at 30 day harvest intervals, the CP remained high and mean values of 18% were obtained. The GFY of Redlan x MB (118,519 kg/ha) during the 211-day growing period was 16.6% higher (P < .05) than that of the male parent MB. CK-60 x MB had 18.7% more DFY and 21.2% CPY than MB (P < .05). No significant differences in height and CP content were observed among the three genotypes. The forage yields and high CP content obtained on MB and the two F1 hybrids were excellent. The results indicate that these genotypes, especially the MB F1 hybrids, are potentially good forage crops for Puerto Rico.