Abstract: Ajakanga landfill located within Ibadan metropolis, southwestern Nigeria was opened in 1998 and still in operation till date. The leachate emanated from decomposed solid wastes have adverse effects on nearby groundwater sources. The aim of this study was to assess the groundwater quality using an indexing approach from existing hand-dug wells bordering this active landfill site and assess its suitability for drinking and domestic purposes during dry and wet season. Ten water samples from different locations within the landfill were identified for groundwater sampling. The samples were collected in March and August, 2013 and analyzed for different physico-chemical parameters. The analyzed physicochemical parameters such as pH, TDS, TH, HCO3¯, CO3¯, Cl¯, NO3¯, SO42¯, Na+, K+, Ca2+ and Mg2+ fall within the standard limits of WHO and NSDWQ. The values of GWQI of water samples during dry and wet seasons were found in the range of 16.8-38.4 and 11.4-48.9, respectively. About 50% of sampling waters belong to “Excellent” water status and 50% under “Good” class during dry season. During wet season, 70% of sampling points come under “Excellent” water status while 30% belongs to “Good” water status. The GWQI value of each well for both seasons revealed their fitness for drinking and human consumption purposes. Pearson’s correlation coefficients among selected water quality parameters show very strong association between EC and TDS in both seasons.