This experiment was conducted to evaluate the physical, fermentative, microbial and chemical characteristics of ensiled Pennisetum purpureum (PP) grass mixed with processed Enterolobium cyclocarpum (EC) seeds at varying proportions and different ensiling periods. The study was a 7×2 factorial experiment in a randomized complete block design. The factors were processed (boiled, toasted and raw) E. cyclocarpum seeds (EC) ensiled with P. purpureum grass (PP) at varying proportions (0:100, 15:85 and 30:70) at two ensiling periods (30 and 60 days). Results showed that processed E. cyclocarpum seeds in P. purpureum grass silage significantly (P<0.05) influenced the physical characteristics of the silage produced. Silage made with 30% toasted EC seeds + 70% PP grass consistently recorded higher values for lactic, acetic, butyric and propionic acids and the lowest pH (5.3) as compared with the others. Silage of 60 days had higher lactic, acetic, butyric and propionic acids than at 30 days. Silage containing 15% raw EC seeds + 85% PP grass recorded significantly (P<0.05) highest lactic acid bacterial contents over the other silages. Higher lactic acid bacteria and total yeast counts were recorded in silage after 30 days. The crude protein contents differed significantly (P<0.05) ranging from 9.92% in 100% PP grass silage to 15.47% in 30% boiled EC + 70% PP grass silage. It can be concluded that the inclusion of 30% boiled EC seeds with 70% PP grass ensiled for 60 days recorded higher silage quality than the proportions and ensiling period.