A case of dysgammaglobulinemia associated with nodular lymphoid hyperplasia of the colon is reported. The patient had typical immunoglobulin deficiency, diarrhea, recurrent respiratory infections, Giardia lamblia in the stool, and lymphoid hyperplasia of the small intestine. His barium enema showed diffuse submucosal nodules. Rectosigmoid biopsy confirmed nodular lymphoid hyperplasia. The similar findings on barium enema in this entity and in lymphosarcoma are stressed.