Studying the impact of economic growth on the environment in the context of developing countries has become of increasing economic importance in recent years. Alarming international reports show that pollutants emissions are growing at their highest level ever, particularly in the South countries. This paper implements recent bootstrap panel unit root tests and cointegration techniques to investigate the relationship between Sulfur dioxide emissions and real GDP for 12 MENA countries over the period 1981–2005. Our investigations lead to the result that no evidence is found for the EKC hypothesis for 10 country of the region. However, the EKC hypothesis is valid for the case of Egypt and Tunisia; the two most industrialised and diversified economies in our sample. At the same time, our findings show that EKC is not valid for the region when considered as a whole.