Background & Aims: It is well known that there is a discrepancy between prescribed and delivered enteral nutrition in intensive care units. So far the contribution of infusion pumps has received little attention. The objective of this study was to assess the role of infusion pump inaccuracy in the supply of enteral nutrition. Design: Observational study over a period of 1 month. Setting: Mixed medical and surgical tertiary academic intensive care unit. Patients: Thirty-two patients receiving full enteral tube feeding. Methods: The delivered amount was calculated from the difference in weight of a bag of nutrition between the starting time and the moment of weighing. The prescribed amount was calculated using the time between onset of the bag and the time of weighing the bag (in hours) times the pump setting (ml/h). Results: Hundred bags (nutritional periods) were weighed in 32 patients. Out of the 100 measurements 36 showed an adequate delivery of enteral nutrition. In 55 measurements patients received less than 90% and in 9 more than 110% of the amount prescribed. Interruption of delivery was the cause in 19% of the cases. Conclusions: Discrepancies between delivered and prescribed amount of nutrition could be attributed to inaccuracy of the pump in 81% of the cases.