Mountain regions are important producers of organic food. For them, reliable decision making regarding business planning necessitates different critical support methods. KARSIM 1.0 (DSM) is a methodology based on an integrated deterministic simulation system application for decision-making support, consisting of 74 deterministic production simulation models. DSM enables different types of cost and financial feasibility calculations for organic production and food processing. KARSIM 1.0 was used to simulate three specific business alternatives for mountain organic farms. (Alternative 1: spelt grain, fruit cider, wine and brandy, plum brandy, calves meat and sheep-soft cheese production, Alternative 2: spelt flour, pear and apple juice, plum brandy, veal and sheep's milk, Alternative 3: spelt grain, dried fruit, calves, soft and hard sheep cheese). Simulation model results were compared using two multi-objective analysis methods: the analytical hierarchical process (Expert Choice Decision Support System software) and DEX-i method. The results showed the highest multi-objective decision evaluation for alternative 2 (Expert Choice = 0.361 and DEX-i evaluation = excellent). We can conclude that the combination of a deterministic cost simulation model and multi-criteria decision analysis presents an acceptable decision support tool for mountain organic farms; however, further research is desirable.