The interaction between diarrhoeal disease and nutritional status measured by anthropometry was investigated in approximately 1000 children aged 1 to 4 years during April-December 1976 in a rural area of Bangladesh. Data on diarrhoeal disease were provided by the mothers interviewed at seven-day intervals. Weight and height data were collected bimonthly. Children classified using anthropometric criteria--weight-for-age, height-for-age, and weight-for-height--were prospectively evaluated for incidence and duration of diarrhoea during a short (two-month) period and a long (eight-month) period. Incidence of diarrhoea was not found to be related to nutritional status measured by any of the anthropometric criteria for any of the periods. But duration of diarrhoea was found to be related consistently to nutritional status measured by weight-for-age and weight-for-height. Diarrhoea in the short term affected weight increment in the short term, but not in the long term and did not affect height increment for any of these periods. Diarrhoea in the long term affected both weight increment and height increment in the long term.