In this study, we retrospectively evaluated all attacks of diarrhoea in our renal transplant recipients that came to our medical attention between 1985 and 2000. Also, the clinical features of patients with diarrhoea were compared with the features of recipients without diarrhoea. We diagnosed 41 attacks of diarrhoea in 39 (12.6%) of 308 renal transplant recipients during this time period. An aetiology was detected in 33 (80.5%) of all diarrhoeal episodes and in seven (17.1%) of those the specific agent was diagnosed with the help of stool microscopy. The most frequent causes of diarrhoeal attacks were infectious agents (41.5%) and drugs (34%). Six (14.6%) episodes of diarrhoea were chronic and six were nosocomial. About two-thirds of diarrhoea developed within the late post-transplant period (> 6 months). When recipients with diarrhoea were compared with those without diarrhoea, it was seen that diarrhoeal patients had significantly higher creatinine and significantly lower albumin levels when compared with the latter group (p < 0.05). Also, the frequency of antibiotic usage was significantly higher in diarrhoeal patients than in the control group (p < 0.05). Four (10.2%) patients with diarrhoea died despite institution of the appropriate therapy. Two of these deaths were primarily related to diarrhoea and the aetiological agent was Clostridium difficile in both these cases. During the 15-yr study period, 3.6% of all deaths and 5.1% of infection-related deaths in transplant recipients were secondary to diarrhoea. As a result, we observed that infections and drugs were the most frequent causes for diarrhoea in our series of renal transplant recipients. Also, diarrhoea was an important cause of mortality in this patient population.