Deficiency of docosahexaenoic acid (DHA) and other omega-3 (omega3) fatty acids may constitute an alterable risk factor for Alzheimer's disease (AD). Mechanisms of potential involvement of DHA in the disease process have been postulated primarily from studies in vitro and in mouse models of AD. Information on the fatty acid profile of the brain in AD itself is limited and in some respects contradictory. Interpretation of the findings is complicated by the diversity of methods used in previous studies and a lack of information as to the effect of post-mortem delay on the results. Here we report the development of a simple and highly reproducible method that enables relatively high-throughput measurement of the fatty acid composition in samples of brain tissue and using this method we have demonstrated that there is no significant change in fatty acid composition under conditions designed to model post-mortem delay of up to 3 days at 4 degrees C (or even at room temperature). The development of this method and the observation that delay of up to 3 days has no effect on fatty acid content will facilitate further studies of fatty acid composition on large cohorts of post-mortem brains.