The argument that stringent environmental regulations are generally thought to harm export flows is crucial when determining policy recommendations related to environmental preservation and international competitiveness. By using bilateral trade data, we examine the relationships between trade flows and various environmental stringency indices. Previous studies have used energy intensity, abatement cost intensity, and survey indices for regulations as proxies for the strictness of environmental policy. The inconclusiveness of the findings of previous studies may be because they overlook both the direct and the indirect effects of regulation. Regulation may increase GDP and thus raise export flows. In addition, the strong version of the Porter hypothesis claims that environmental regulation enhances economic performance-at least in the medium run-for compliant firms, the sector to which they belong, and, eventually, the economy as a whole. In particular, Costantini and Mazzanti (2012) find evidence in support of the strong Porter hypothesis.The contradictory nature of the results of previous research might also be driven by authors using various proxies of environmental variables. Energy intensity, abatement cost intensity, and survey indices have been generally used as proxies for the stringency of regulations. However, each of these proxies is distinct. Energy intensity, defined as energy use relative to the gross domestic product (GDP), is likely to reflect regulations that are strongly related to energy, whereas abatement cost intensity, defined as abatement cost relative to GDP, tends to reflect regulations that relate to a relatively wide range of industries. Moreover, previous works have typically used three survey whether the strong version of the Porter hypothesis is confirmed and (ii) the overall effect of regulation on export flows.The remainder of the paper is organized as follows. The next section presents the background. Section 3 explains our model and Section 4 discusses the empirical results.