The influence of bovine lactoferrin (LF) and Apo-LF on growth of Listeria monocytogenes in Ultra-High Temperature (UHT) 2% fat milk was determined. The effect of LF was dependent upon both the degree of iron saturation and concentration. Before iron removal, LF was found to be approximately 52% saturated with iron; and at 23 and 46 mg/ml LF, minimal growth inhibition of L. monocytogenes was observed. Following dialysis, Apo-LF iron saturation was reduced to approximately 18%. At 15 and 30 mg/ml Apo-LF, a bacteriostatic effect against L. monocytogenes was observed. Inhibition of growth associated with Apo-LF was abolished when ferric ammonium citrate was added to saturate the iron binding sites of the Apo-LF.