Worsening of long-lasting diarrhea, abdominal discomfort and weight loss were main symptoms in a 27-year-old Moroccan woman who had lived in Germany for 18 years. Pseudomonas, salmonella and lamblia cysts were found in stools. Histological examination of the gastrointestinal tract showed immunoproliferative small intestinal disease (IPSID), characterized by atrophy of the villi and lymphoplasmocytic infiltrates. alpha 1-heavy chains were found immunohistologically in the biopsy specimen, but not in serum, urine or jejunal juice. HLA-typing gave evidence of A9. Antibiotic treatment was successful for almost one year. Clinical, histological and immunological diagnosis of IPSID in an African woman living for nearly 20 years in Europe shows that, besides environmental factors, genetic disposition is an essential factor in the development of IPSID.