Like other economic sectors, agriculture requires the efficient use of resources and farming inputs, considered as a key factor for sustainability. On the other hand, the ecological limitations of the productivity in mountains make the study of efficiency in agricultural systems in these areas even more crucial. Material and methods Based on these assumptions, we present in this study the preliminary results of efficiency analysis in four farms representative of farming systems, in mountain regions in Portugal: a) Douro vineyards (60ha), b) olive grove (15ha), c) mixed-farming (36ha), and d) chestnut orchards (10ha). These are rainfed agriculture systems in small/medium-sized farms, consisting of several blocks, with the exception of the in Douro vineyard, which has a single block.