In this study, the Tool for the Reduction and Assessment of Chemical and other Environmental Impacts (TRACI) of the United States Environmental Protection Agency and the methodology of the Centre for Environmental Studies (CML) of the University of Leiden are two approaches applied as provided for in the GaBi₅ (Holistic Balancing) Life Cycle Assessment (LCA) software database, to classify and characterize environmental impacts of municipal wastes in Ogbomoso South Local Government Area (LGA), Nigeria. On waste composition, 5 representative households were selected, each from the cardinal polling units in Ibapon (ward 4) for the study. Wastes samples were collected from the households over a period of 5 days, sorted, classified according to their constituents and weighed accordingly. For the Life Cycle Impact Assessment (LCIA), two waste management scenarios/models were developed and compared using GaBi₅ software. Scenario 1 involves collection, transportation and landfilling, while Scenario 2 ends with incineration. The Impact Indices determined from both scenarios were: Global Warming Potential (GWP), Acidification Potential (AP), Eutrophication Potential (EP) and Ozone Layer Depletion Potential (ODP). Findings show that the overall mean percent (%) wastes composition for biodegradable, metal, textile, paper, plastic, glass and wood were respectively found to be 55.9, 9.5, 2.4, 6.5, 6.7, 6.6, and 12.2. From the results of LCIA methods studied, landfilling of wastes poses a lesser burden on the environment, using the ODP index, as compared to incineration. It is concluded that of the management scenarios considered, landfilling of wastes is more environmentally friendly and therefore recommended for use in the study area.