Intake of milk and butter has been clearly associated with higher coronary heart disease rates in different countries and this is likely to be mediated by the hypercholesterolemic effect of dairy fat. Fat-modified dairy products are an innovation involving a technology in which protected unsaturated lipids are fed to ruminants resulting in milk and tissue lipids with reduced saturated fatty acids. We examined the impact of these novel dairy fats on plasma lipids in a human dietary trial. Thirty-three men and women participated in an 8-wk randomized crossover trial comparing fat-modified with conventional dairy products. The trial consisted of a 2-wk low-fat baseline period followed by two 3-wk intervention phases. During the test periods, the fat-modified products resulted in a significant 0.28-mmol/L (4.3%) lowering of total cholesterol (P < 0.001). Most of this decrease was in LDL cholesterol, which decreased by 0.24 mmol/L (P < 0.001) whereas HDL cholesterol and triacylglycerols remained essentially unchanged. This alteration in the fatty acid profile of dairy products, if applied to populations typical of developed Western countries, represents a potential strategy to lower the risk of coronary heart disease without any appreciable change in customary eating patterns.