This paper documents phytochemical variation of European cranberry (Oxycoccus palustris Pers. = Vaccinium oxycoccos L.) growing in peatlands of North-Western Poland. Thirty four fruit samples collected in 2008–2009 at 15 sites in northern Wielkopolska (Greater Poland) and Western Pomerania were used in the study. The flavonol content, expressed as quercetin equivalent, was determined spectrophotometrically. The amount of main organic acids: citric, malic, and quinic, was determined using the HPLC-DAD method. The obtained results show high phytochemical differentiation of European cranberry fruit. The flavonol content ranged from 57 to 298 mg% of dry matter. The organic acids in question accounted for, respectively: 8.57–21.32% (citric acid), 2.18–14.24% (malic acid), and 2.96–8.79% (quinic acid) of fruit dry matter. There was also a large variation in the ratio of quinic acid to malic acid (from 0.27 to 3.83). A strong negative correlation was found between the abovementioned acids (r= -0.74, p=0.000). This indicates the possibility of occurrence of two chemotypes of European cranberry, differing in the content of quinic acid and malic acid.