Abstract The purpose of this study was to determine if, as has been reported in the literature, cobaltous ions form stable complexes with the enediol form of the ketol side chain of 11-deoxycorticosterone. After incubation of the steroid with cobaltous or ferrous ions, extensive destruction of the ketol side chain occurred. This was diminished when conditions of scrupulous cleanliness (as defined in this paper) were observed. Incubation of cobaltous ions with 11-deoxy-[4- 14C, 21- 3H]-corticosteroids did not result in tritiumprotium exchange with the medium that was expected if an enediol formed. We conclude that the enediol configuration does not result from the interaction of 11-deoxycorticosterone and metal ions.