The influence of grape assortment in terms of assortment size and product function/product consistency on the technical efficiency of grape-growing family farms in Macedonia was analyzed. A two-stage Data Envelopment Analysis (DEA) method extended with bootstrapping was applied to the three-year average (2006-2008) of a panel dataset for 300 farms. In the first stage, output-orientated ordinary DEA and bias- corrected technical efficiency scores accompanied with confidence intervals were obtained. In the second stage, the impact of grape assortment characteristics on the efficiency scores obtained was assessed. The analysis revealed very high potential for revenue increases. Farmers with lower variety diversification, specializing in growing local and regional varieties and table grape varieties, achieved higher efficiency. Thus the ongoing revitalization and investments in Macedonian grape assortment should primarily be directed towards regionally recognized and table grape varieties. Grape variety diversification is generally not recommended.