Abstract: A research was conducted during growing season of 2005 to study the effects of irrigation regimes and row arrangement on yield, yield components and seed quality, oil percentage, germination index, germination percentage and seedling growth parameters and vigority of pumpkin (Cucurbita pepo L.). Three irrigation intervals of 7, 14 and 21 days and different plant spacing of 100x20, 100x40, 200x20 and 200x40 cm were used. Results indicated that the highest seed yield of pumpkin was observed in irrigation interval of 7 days, but it was not a significant difference between 7 and 14 days irrigation intervals. Irrigation intervals have a significant effect on number of seeds per fruit and the highest amount was observed in irrigation intervals of 7 days. Increasing irrigation interval up to 21 days decreased significantly the number of seeds per fruit and consequently seed yield per unit area. The highest seed oil yield was observed in irrigation interval of 7 days. Irrigation intervals had not significant effects on germination index and germination percentage of pumpkin but significantly affect lengths and wet weights of primary root and hypocotyls and vigority in pumpkin seeds. Results showed that the highest seed yield of pumpkin was obtained in 100 cm row distances in compare to 200 cm. Row distance had not a significant effect on number of seeds per fruit, but the highest fruits number was observed in lower row distances. Germination index and germination percentage were not affected by row distances but the highest root and hypocotyl lengths and wet weights and also seed vigority were observed in higher distances. Between row distances did not have a significant effect on evaluated parameters. The most favorable interaction treatment for seed yield and seed oil yield of pumpkin was irrigation interval of 7 days and plant spacing of 100x40 cm (25000 plants ha-1).