The fatty acid composition of triacylglycerols from fifteen distinct adipose depots taken from each of seven adult male human subjects was compared. Oleic, palmitic, linoleic, stearic, myristic, palmitoleic and vaccenic acids accounted for more than 90% of the triacylglycerol fatty acids in all sites from all subjects; a number of other fatty acids were also identified and quantified. There were large differences in the average fatty acid composition between individual subjects. There were no site-specific differences in the proportions of myristic (3.8-4.7% of triacylglycerol fatty acids), palmitic (23-29%), linoleic (6.7-9.8%) or vaccenic (4.1-4.7%) acids or in the proportions of any of the less abundant fatty acids. There were some significant site-specific differences in the proportions of palmitoleic, oleic and stearic acids. The calf depot contained more palmitoleic acid (6.41 +/- 1.09%) than the trapezius (3.12 +/- 0.55%), perirenal (3.59 +/- 0.50%) and mesenteric (3.70 +/- 0.43%) depots, more oleic acid (42.13 +/- 1.27%) than the trapezius (36.03 +/- 2.18%), perirenal (36.50 +/- 1.56%) and breast (37.13 +/- 1.55%) depots and less stearic acid (5.18 +/- 0.89%) than the trapezius (8.57 +/- 0.97%), perirenal (8.49 +/- 0.75%), mesenteric (7.87 +/- 0.42%), breast (8.02 +/- 0.75%) and clavicular (8.34 +/- 0.78%) depots. The buttock depot contained less stearic acid (6.06 +/- 0.65%) than the perirenal, mesenteric and clavicular depots, while the anterior thigh depot contained less stearic acid (6.07 +/- 0.70%) than the perirenal depot. These findings indicate that, while most human adipose depots differ little in fatty acid composition, some sites, in particular the calf, perirenal, trapezius and mesenteric depots, have site-specific properties.