The very heterogeneous, but non-random, arrangement of lipids and proteins in cell membranes, known as rafts are of major scientific interest. Lipids in cell membranes are continually under attack from reactive oxygen species with the result that new, oxidized species of lipid are continually being formed. Although oxidized lipids have implications in cell apoptosis, cancer and aging, very little work has been performed to understand the effect of oxidative lipid damage on raft formation. We propose, therefore, to use specular and off-specular neutron reflection in combination with contrast variation to probe the effect of the presence of oxidized lipid on the persistence and size of rafts formed. These studies will allow a better understanding of the factors leading to the formation of microdomains in biological membranes and in particular the influence of oxidation thereupon.