This paper uses a dynamic panel data for 23 OECD and 50 non-OECD countries for the time period 1960-1990 in order to estimate the relationship between economic development (in the form of GDP) and environmental pollution (in the form of sulphur emissions). Panel data econometric techniques are applied for performing our empirical estimation. The analysis shows significant differences between the most industrialized countries and the rest of the countries considered.