In the climatic conditions of Poland the temporary lack of rainfall during the vegetation season, influenced on the water deficits in the top soil level. This situation can effect on the height and quality of yields in particular years. There is estimated that in the - so called - Large Valleys Region the water deficiency ranged 200-300 mm. Production of cucurbit's vegetables in open field is strictly connected with thermal-rainfall conditions during the vegetation season. The optimal soil moisture is the very important factor for high and good quality yield. So, the production of the cucurbit plants should be connected with the irrigation installations. The aim of the study was to determine the influence of drip irrigation in cultivation of summer squash ‘Danka' under light soil conditions. The trials were conducted in the years 2004 - 2006 at the experimental field in Kruszyn Krajeński near Bydgoszcz - on a soil of rye weak complex. The plot area for harvest was 9,1 m2. The irrigation rates were done on the base of soil water potential according to tensiometer indications. The irrigation was started when the soil water tension was - 0,04 MPa. The fruits of the summer squash were harvested in the technological maturity in the second decade of September in each year of the study. The single weight and number of the fruits as well as marketable yield from the unit area were estimated. In the pulp the dry matter, vitamin C, sugars and carotenoids content were determineted. It was found that drip irrigation significantly increased the marketable yield of fruits. The higher yield increases were detected in the years with lower rainfalls. The significant influence of drip irrigation on the content of vitamin C and sugars was stated. The dry matter and carotenoids content were higher in the fruits from the irrigated plots, but the difference was insignificant.