Nurses are forced to make decisions about feeding tube position at regular intervals during the delivery of tube feedings; failure to detect an improperly positioned feeding tube can have serious consequences. This study was designed to determine the extent to which specific indicators could singularly and collectively differentiate between gastric and small-bowel placement in patients with nasally or orally inserted small-bore feeding tubes. Indicators were the length of tubing extending from the tube's insertion site as well characteristics of aspirates withdrawn from the feeding tube (volume, appearance, and pH). A total of 201 critically ill tube-fed patients participated in the study for a period of 2-3 days. Among the inclusion criteria were an order for the blind insertion of a small-bore feeding tube, orders to start continuous feedings, and radiographic confirmation of tube location. Five times daily, the following variables were measured: (a) length of tubing extending from the insertion site, (b) volume of aspirate from the feeding tube, (c) appearance of the aspirate, and (d) pH of the aspirate. At the time of entry into the study, 85 patients had gastric feeding tubes and 116 patients had small-bowel feeding tubes. A total of 2,754 concurrent measurements of the variables were attempted; sufficient fluid for pH testing and color description was obtained in 74.2% of the attempts from gastric tubes and in 62.2% of the attempts from small-bowel tubes. Univariate analysis showed that all four of the variables described above were able to differentiate between gastric and small bowel tube sites. A multivariate, forced entry, logistic regression model was able to correctly classify tube site in 81% of the predictions. A variety of easy-to-use bedside methods can be used with a moderate degree of confidence to distinguish between gastric and small-bowel tube placement during continuous feedings.