The authors report two cases of malignant tumours of the small intestine (one adenocarcinoma and one lymphoma). In both patients, longstanding anemia with hypochromia and decreased serum iron remained unexplained for some time. Iron was prescribed without definite diagnosis. These two cases demonstrate the extreme latency of these tumours and the necessity for detailed intestinal investigations in patients presenting with isolated hypochromic hyposideremic anemia. Among these investigations, doubla contrast roentgenographic study of the small intestine appears to be an adequate diagnostic procedure for disclosing even very small lesions.