To investigate the occurrence of tropical pulmonary eosinophilia (TPE), studies were undertaken in 3 villages with endemic lymphatic filariasis in the coastal area of Tanga Region, Tanzania, and in the outpatient clinic of Bombo Regional Hospital in Tanga town; 73 persons from the villages and 104 from the outpatient clinic with a history of lung disease suggestive of TPE were included in the study. Following clinical examination, lung function tests and chest X-rays were performed. Total leucocyte and eosinophil counts were recorded. Parasitological examinations included blood for microfilariae and stools and urine for eggs of intestinal helminths and Schistosoma haematobium respectively. Total immunoglobulin (Ig) E and specific antifilarial IgE and IgG4 were measured. Suspected TPE cases were treated with diethylcarbamazine, 6 mg/kg for 12 d, and were followed up 14, 90 and 360 d after treatment. Three persons fulfilled the criteria for TPE. Their response to treatment was marked, with clinical improvement, reduction in eosinophil count and reduced titres of specific antifilarial IgE and IgG4. Although TPE is present in Wuchereria bancrofti endemic areas of East Africa, it appears to be rare, as in other endemic areas.