The metabolic fate of 9-fluoro-11beta,16alpha,17,21-tetrahydroxy-1,4-pregnadiene-3,20-dione cyclic 16,17-acetal with 2(-14)C-acetone, triamcinolone acetonide (TA) was studied in rabbits, dogs, monkeys and rats and found to be qualitatively similar in all species. In the dog, rat and monkey the major excretory route was the feces irrespective of the mode of administration. In the rabbit the excreted radioactivity was equally distributed between urine and feces. The metabolites were isolated by preparative thin layer chromatography, located by autoradiography, eluted and analyzed by MS, IR, UV and NMR. The major metabolites of triamcinolone acetonide (TA) were identified as the C-21 carboxylic acids of TA and of the 6beta hydroxy-TA, (6BETA-OH-TA) and the previously identified (1,2) 6beta-OH-TA. In addition MS and UV data indicate the presence of 9-fluoro-11beta,16alpha, 17-trihydroxy-3,20-dioxo-1,4,6-pregnatrien-21-oic acid cyclic 16,17 acetal with 2(-14)C-acetone.