In this article we assess the impact of agri-environmental subsidies on farms’ technical efficiency, when the latter is measured with and without accounting for greenhouse gases (GHGs). The application is to a sample of beef cattle farms located in grassland areas in France during the 1993-2013 period. In a first stage we calculate robust technical efficiency accounting for both good output (meat) and bad output (GHGs). In a second stage we regress the different technical efficiency scores on a set of explanatory variables including agri-environmental subsidies as an amount received by the farmer related per livestock unit. The results indicate that these subsidies had a positive impact on farms’ technical efficiency among the farmers that have adopted agri-environmental measures. This is the first work on the effect of subsidies on technical efficiency including environmental outputs, and it does not confirm the negative effect generally found in existing studies based on classic technical efficiency.