The aim of the study is to evaluate effectiveness of a rainwater harvesting technique with polyethylene film covered ridges (RHCR) on pumpkin seed production under rain-fed conditions in Kayseri/Turkey. For this purpose, a two-year experiment, of which were consisted three covered ridge widths (R1= 0.5, R2= 0.7, and R3= 0.9 m) and a control treatment, was conducted. The experimental design was completely randomized plots in blocks with three replications. Significantly higher seed yields were obtained from R2 and R3 (202 and 208 kg ha-1) in first year and from R2 (660 kg ha-1) in second year. Although excessive drought conditions were experienced during pumpkin growing period in those years, especially R2 treatment resulted significantly higher yield. Higher plant density in R1 and lower density in R3 negatively affected seed yield especially in water scarce second year. In second year, leaf area, mean fruit weight, fruit yield, seed yield and 1000-seed weight were found higher than ones in first year because of application of nitrogen a whole at sowing. We concluded that RHCR with optimum plant density and proper covered ridge wide, and application whole nitrogen at sowing under rain-fed conditions are effective ways to obtain higher pumpkin production in semiarid regions.