This paper aims to assess whether and to what extent environmental and productivity affect each other within heterogeneous farms. The analysis concerns the sample of FADN Lombardy farms observed from 2008 to 2013. Using the FADN information on production structures and activities, a productivity index (Total Factor Productivity - TFP) and an environmental indicator (Emission Intensity - EI) are properly reconstructed at the farm level. The nexus between TFP and EI is then investigated by admitting heterogenous behaviour across farm sizes and specializations. Results show that the relationship between TFP and EI is not univocal and suggest that the mitigation of GHG emission can be based on the diffusion of the best practices adopted by high-productivity farms of different size and specialization.