Gas chromatographic analysis of tissue lipids from broiler chickens dying from sudden death syndrome (SDS) were carried out to determine if anomalies in fatty acid composition could be linked to the disease. Crude extracts of lipids from hearts and livers of chickens dying from SDS and their matched controls (matched for pen number, sex and time of death) were fractionated by thin layer chromatography and the phospholipid, triacylglycerol (TG) and nonesterified aliphatic carboxylic acid [C14-C22] (FA) fractions were transmethylated and analysed by capillary gas chromatography. A number of significant (P less than .05) differences in fatty acid composition were found to exist between males dying of SDS and their controls, the most notable being elevated levels of arachidonic acid in the hepatic TG and cardiac FA fractions of SDS males. Few significant differences were found between SDS females and their controls. There was a trend toward increased desaturation of cardiac and hepatic tissue lipids of male SDS chickens, although this was significant only for the hepatic TG fraction. The results did not support the hypothesis that a lack of arachidonic acid as a precursor of prostaglandin synthesis was a causative factor in the disease.