The anti-inflammatory, liver glycogenic, and Na retaining activities of a series of 6[alpha]-fluoro and 16[alpha]-methyl steroids and their parent compounds were determined. The 6[alpha]-fluoro substitution increased liver glycogenic activity in all compounds studied, and anti-inflammatory potency in all but one of the compounds. This modification also produced variable effects on Na retention. The 16[alpha] -methyl group did not consistently increase liver glycogenic or anti-inflammatory activities. Na retention effect of the corticoids was not increased by 16-methylation if the parent compound did not possess mineralocorticoid activity. In examples where parent steroid was a Na retainer, addition of 16a-methyl group caused reduction of this activity.