This study reinvestigates empirically the Environmental Kuznets Curve (EKC) hypothesis. According to this hypothesis, there is an inverted U-shaped relationship between environmental degradation and economic growth. The available EKC literature, in general, employs CO2 emissions as a proxy for environmental degradation. Unlike the current studies, this study employs the Ecological Footprint (EF hereafter) variable, instead of CO2 emissions, as an indicator of environmental deterioration. Then, this research observes the countries which are classified into three income groups in order to investigate EKC hypothesis. In conclusion, following the second generation panel data techniques, this paper reaches its best fitted model among the models of continuously updated fully modified (CUP-FM) and continuously updated bias corrected (CUP-BC) models, and, reveals that EKC hypothesis is confirmed by low income, middle income and high income group countries' data. (C) 2018 Elsevier Ltd. All rights reserved.