Abstract The aim of the study was to evaluate the occurrence of Alaria alata in red foxes in NW Poland. The extensity of infection with Alaria alata was 54.7%, and the mean intensity of infection was 72 individuals per host, ranging in number from one to 769 individuals. The fluke was found in the three parts of the small intestine, but more often in the jejunum and duodenum than the ileum. Statistically significant differences in fluke number were found between the duodenum and ileum and between the jejunum and ileum. The presence of Alaria alata was observed more in the western districts, large surfaces of which are covered by water reservoirs: these allow Alaria alata flukes to complete their developmental circle.