Twelve premature infants were studied prospectively to determine the extent and pattern of bacterial contamination in nasogastric tube (NGT) milk residues. Of the 60 NGT milk residue samples cultured, 49 (82%) had bacterial isolates; 34 (69%) samples with multiple organisms. Gram negative organisms were the predominant species; Klebsiella spp. (32%), Pseudomonas spp. (16%), Acinetobacter spp. (14%), Enterobacter spp. (11%) and Escherichia coli (11%). The antibiograms of these organisms indicated the environment as the main source of bacteria for the NGT colonisation. However, the relation-ship of high rates of isolation of potentially pathogenic bacteria in NGT milk residues and the risks of infection to these infants is unclear and needs further evaluation.