The aim of the study was the determination of the nitrates content in the giant pumpkin and studying of changes in contents of these compounds during the storage. Experimental material determined 3 new hybrids (956, 957, 958) and 2 registered varieties (Karowita and Bambino) of giant pumpkins. Fruit harvest was conducted in 21 September 2005. Research passed became into 4 periods: I period directly after the harvest, II – 4 weeks after the harvest, III – 8 weeks and IV period – 12 of weeks after the harvest of fruit. Pumpkins were stored at first in the folic tunnel and next in the cold storage room at 10ºC and humidity was 75%. The content of the nitrates(V) in investigated variations of giant pumpkin was very different. Directly after the harvest time the amount of nitrates was from 20.7 mg/kg of the fresh mass (956) to 282.7 mg/kg f.m. (Bambino). During the storage this content successively declined and for 12 weeks the nitrate content was lower even for 62.2%. The content of the nitrates(III) in studied giant pumpkins varieties amounted from 0,02 mg/kg f.m. (Karowita) to 0.08 mg/kg f.m. (956) in the first period of research. For the all of varieties of giant pumpkin the inconsiderably increase of the content of nitrates (III) during the storage time was detected.