1.   We have previously reported two cases associated with chronic diarrhoea, failure to thrive and a proximal small intestinal enteropathy.

2.   The association between a proximal small intestinal enteropathy and cryptosporidiosis in man has not been well established.

3.   In this study there was a remarkably consistent proximal small intestinal enteropathy of mild to moderate severity.

4.   We conclude that Cryptosporidium is an important cause of chronic diarrhoea with failure to thrive in immunocompetent children and is associated with a proximal small intestinal enteropathy.