The study was published in “Ecological Indicators”. Energy analysis in peach orchards is useful to decide best management strategies. The objectives of this study were to evaluate (a) the energy flow among conventional, integrated and organic farming systems and (b)the effect of farming system to greenhouse gas-emissions. Sixteen farms (four conventional, nine integrated, three organic) at six locations in northern Greece were selected randomly during the years 2008 and 2009. Multidimensional data analyses were used to detect (a) clusters of farming systems and (b) associations between farming systems and production coefficients variables. Three groups of farming systems and three groups of variables were revealed. Farming systems in the same group respond more or less similarly to the production coefficients variables. Non-parametric tests concerning external variables (outputs, energy efficiency, fruit production, CO2, CH4 and N2O) showed that the variables in organic farming cluster were at average significantly lower. Similarities and/or dissimilarities among farming systems, can probably be related to farm topography, production coefficients and local farming practices. The results showed that organic farming could reduce inputs and gas-emissions.