A field trial was conducted between February and May 2015 at National Biotechnology Development Agency (BIODEC) Centre Owode Yewa South, Ogun-State Nigeria to evaluate the influence of matured poultry manure on the growth and yield of guinea grass (Pannicum maximum Jacq). The treatments consisted of T1 0.5kg/M2 bed (Equivalent of 5.0 Metric tonsha-1), T21.0kg/M2 bed (Equivalent of 10Metric tonsha-1), T3 1.5kg/M2 bed (Equivalent of 15Metric tonsha-1) and T4 No application (control).The experiment was laid down in a Randomised Complete Block Design (RCBD) replicated four times. The treatments were applied onto the beds uniformly and mixed thoroughly; planting was done one (1) week after application. Plant height, number of tillers generated and fresh weights of twelve (12) randomly selected plants were taking from within the three (3) middle rows at fifth 5th week after planting, third 3rd week after the first harvest and third 3rd week after the second harvest. The data collected were subjected to a univariate General Linear Model (GLM) two ways Analysis of Variance (ANOVA) using IBM SPSS software statistical package 21.Significance mean differences were separated using Fisher’s Least Significant Difference (LSD) at 5 percent level of confidence. The results showed that there was no significant (P > 0.05) difference in the treatments effect on plant heights during the 1st and 2nd harvest, subsequently significant difference (P< 0.05) existed on the grass in term of all the parameters measured. Mature poultry manure dosage treatment (T2)1.0kg/M2 bed (Equivalent of 10Metric tonsha-1) was observed to be the best and thus recommended for dissemination and use by farmers in the ranches, paddocks and in forage home gardens.