Biogas generated from various agricultural wastes was subjected to compositional analysis so as to assess the quality of the biogas in terms of the methane, carbon (IV) oxide, and hydrogen sulfide content. On the basis of methane content paper waste has the highest quality biogas with 72.59% this is followed by saw dust with 68.79%, followed by cow dung with 66.00% and then rice husk with methane content of 64.97% the substrate that produced biogas with the lowest percentage methane is millet husk which gave 58.08% . The quality of biogas is also evaluated in terms carbon (IV) oxide content, the higher the carbon (IV) oxide content the lower biogas quality, base on this the highest percentage of CO2 of 40.72% was recorded for millet husk this is followed by 33.00% for both cow dung and rice husk., saw dust gave 29.65% making it as substrate with the second best quality biogas after paper wastes which recorded the lowest percentage of CO2 (24.27%) which is the best. The other parameter used as the measure of the quality of biogas is hydrogen sulphide content, based on this, biogas sample from cow dung and millet husk have the lowest value of H2S percentage content and therefore of higher quality compared to biogas from saw dust that contain 1.53 % H2S. Rice husk with H2S content of 2.00% has a better quality compared to biogas sample from paper waste which is poorest in terms of H2S content.