Intrauterine growth restriction (IUGR) may influence adrenocortical function, lipid metabolism and glucose tolerance in later life. Both cortisol (F) synthesis and metabolism contribute to serum F concentrations. 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) enzyme converts F to biologically inactive cortisone (E). Decreased 11beta-HSD2 activity has been suggested for a reason to IUGR and to its metabolic consequences. Our aim was to develop a specific liquid chromatography - tandem mass spectrometry (LC-MS/MS) method for analysing serum F and E concentrations, to determine the F/E ratios, and to correlate them with serum lipid concentrations, insulin resistance index (HOMA-IR), and catch-up growth in children born small for gestational age (SGA). The mean serum F and E concentrations, and F/E ratios did not differ between the SGA and their control children at 12 y age. The SGA children in the highest F/E ratio quartile had poorer gain in height between 0-12 y, and higher serum total and LDL cholesterol levels than those with lower F/E ratios. In logistic regression analysis, high LDL cholesterol, high HOMA-IR, and early pubertal stage associated with high F/E ratio in the SGA children. In conclusion, our LC-MS/MS method enables a reliable measurement of both F and E concentrations from a single serum sample. High serum F/E ratio may be associated with IUGR, its metabolic consequences, and poor catch-up growth in a subset of SGA children.