This trial was conducted to assess the agronomic traits and forage dry matter yield of six Pennisetum purpureum grass genotypes in the rift valley of Ethiopia. The experiment was carried out for four consecutive years in randomized complete block design with three replications. Diammonium phosphate (DAP)fertilizer at the rate of 100 kg/ha was uniformly applied at planting and additionally urea at the rate of 50 kg/ha was top dressed after each forage harvesting. Data on plant height, tiller number, dry leaf stem ratio and forage dry matter yield were analyzed using the general linear model procedures of SAS and least significance difference was used for mean comparisons. Combined analysis indicated that the tested genotypes varied significantly (P<0.05) for plant height at harvest, number of tillers per plant, dry leaf stem ratio and forage dry matter yield. Genotype 16788 gave the longest mean plant height while standard check (Zehone-03) gave the shortest value. The highest mean number of tillers per plant was recorded for genotype 14983 followed by 16788, Zehone-03,16808 and 14984 genotypes, respectively while the lowest was recorded for genotype 15743. The highest dry leaf stem ratio was measured from genotype 14983 and Zehone-03 followed by 14984, 15743 and 16808 genotypes, respectively while genotype 16788 gave the lowest value. Genotypes 14983 and 15743 gave the highest herbage yield while the lowest was from genotype 16808 and standard check (Zehone-03). In general, Pennisetum purpureum grass genotypes showed variations in terms of agronomic performance and herbage yield at the study area.