This study was performed to confirm the existence of immunoproliferative small intestinal disease (IPSID) in Pakistan. Clinicopathological features of 12 patients with histologically confirmed disease were analysed. Patients were mostly young males with median age of 24.6 years. Two thirds belonged to poor socioeconomic class. Main presenting features were chronic diarrhoea and weight loss. Eleven patients had radiologic evidence of malabsorption syndrome. Endoscopic findings of mucosal thickening, edema, and flattened villi were present in the majority. Patients had both secretory and non-secretory types of disease. Six patients presented with stage A disease. Four responded to antibiotics or steroids, although mucosal abnormalities persisted in three. Two stage A patients evolved into stage C disease, one was lost to follow-up, the other is alive with disease. Three patients presented with stage B disease. Two responded completely to chemotherapy, the third refused treatment and expired after 16 months. Three patients had stage C disease at diagnosis. They received aggressive combination chemotherapy and remain in complete remission with a median follow-up of 2.2 years. This is the first series of patients with IPSID reported from Pakistan. Clinicopathological features and therapeutic results are consistent with the experience elsewhere. Increased awareness may result in early diagnosis and better management.