Without a doubt, plants take up toxic substances such as heavy metals which are transferred along the food chain. These constrain should not be overlooked due to the importance of vegetables in the human diet, hence this study was aimed to determine the heavy metal concentrations in green leafy vegetables from Oluku dumpsite and a nearby farm during the dry season (2020) and the rainy season (2021). In this study, samples (green leaves, water leaves, bitter leaves and fluted pumpkin leaves) were randomly collected and analyzed using the dry ashing method and atomic absorption spectrophotometry method. Results obtained showed that chromium and manganese concentrations were above the permissible limits set by FAO/WHO guideline values in all the samples, except bitter leaves which were within the FAO/WHO safe limit. The other heavy metals (mercury, lead, cobalt, cadmium and copper) analyzed were below the detectable limit of the atomic absorption spectrophotometer used. This study revealed that dumpsites and lands close to the dumpsite should not be used in the cultivation of vegetables because green leaves, water leaves and pumpkin leaves bioaccumulated chromium and manganese above the FAO/WHO safe limit for consumption.