The effects of row spacing (25, 50, 75 and 100 cm) and sowing rate (4, 8 and 12 kg ha-1 ) on alfalfa (Medicago sativa L.) seed yield and its components were investigated under Mediterranean conditions throughout the years of 2008-2011. In the study cultivar Nimet was used and it was evaluated for number of pods per raceme, number of seeds per pod, biomass yield, harvest index, thousand seed weight and seed yield. The results of the study indicated that row spacing and sowing rate significantly affected biomass yield and harvest index but no significant differences were found in pod number and thousand seed weight. Seed yield was significantly affected by sowing rate. The highest and the lowest seed yield were recorded in the first and third years of the experiment, respectively. The highest seed yield averaged over three years was obtained from 25 cm row spacing with 4 kg ha-1 seed rate while the lowest one was obtained from 75 cm row spacing with combining 4 kg ha-1 seed rate. Results of this study suggest that among the various row spacing and seeding rates, narrower row spacings (25 cm or 50 cm) with the lowest seeding rate (4 kg ha-1 ) were found to be better treatments for alfalfa seed production under Cukurova ecological conditions.