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 ($R_1$= 0.5, $R_2$= 0.7, and $R_3$= 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 $R_2$and $R_3$ (202 and 208 kg $ha^{-1}$) in first year and from $R_2$ (660 kg $ha^{-1}$) in second year. Although excessive drought conditions were experienced during pumpkin growing period in those years, especially $R_2$ treatment resulted significantly higher yield. Higher plant density in $R_1$ and lower density in $R_3$ 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.