An epidemic of trichinosis occurring in a group of 587 German prisoners of war was studied. The source of the infection was uncooked pork served during Dec, 1945, in the prison mess. 83 men required hospitalization. The epidemic was considered mild. Symptomatology consisted of fever, headache, malaise, muscle pain and soreness. Swollen eyelids and eosinophilia were present in a majority of the hospitalized cases. Treatment was symptomatic. Average hospital stay was 26 days. White blood counts on hospitalized cases varied from normal limits to 28,000 per cu. mm.; 45% showed an eosinophilia between 20 and 40%. The highest eosinophile count was 61%. The sedimentation rate was within normal limits in 51% of the patients. Muscle biopsies on 10 patients revealed interstitial myositis and in 2 cases larval forms of Tri-chinella spiralis were found. Skin tests with commercial Trichinella extract (1:10,000) were done on 81 cases. There was a delayed reaction in 49.4%, an immediate positive reaction in 34.6%, and a negative skin test in 16%. 437 prisoners who were not hospitalized had blood smears taken. Of this group 58.8% had an eosinophilia ranging from 0 to 4%, 22.9% from 5 to 9%, and in 18.3% it was 10% or more. Based on studies up to one week following the last improperly prepd. meal in the prison mess, it was estimated that at least 139 prisoners were trichinized. The presence of the disease was suspected in an additional 100 prisoners whose eosinophile counts ranged from 5% to 9% on the same date.