This study investigated the solid waste characterization of the city of Kocaeli. With this aim solid waste groups were analyzed for sub-municipalities of the city. Representative sampling points were determined in municipalities with populations over 5,000. Four different socio-economic groups (the downtown district plus low, intermediate, and high income levels) were investigated in the study. Characterization studies were performed for a 2-year period. In this context, 16 and 13 different solid waste species were categorized for winter and summer seasons, respectively.