The relationships between the adipose tissue concentrations of 19 geometric and positional fatty acid isomers and 10 cardiovascular disease risk factors were determined in 76 free-living adult males. The percentages for trans isomers (total mean +/- SD 4.14 +/- 0.97%) and cis isomers (total mean +/- SD 2.91 +/- 0.34%) in adipose tissue generally agreed with dietary estimates based on the consumption of hydrogenated oils. A major exception was the percentage of 11c-18:1, which was twofold higher in adipose tissue. The total level of fatty acid isomers in adipose tissue or a factor (derived by factor analysis) that was representative of isomers of dietary origin was not significantly correlated with the cardiovascular risk factors. Only three trans isomers (11t-18:1, 12t-18:1, and 5t-14:1) and three cis isomers (11c-18:1, 13c-18:1, and 7c-16:1) were weakly correlated either positively or negatively with age, body mass index, plasma and lipoprotein cholesterol, and/or blood pressure (P less than 0.05, r greater than 0.231).