Abstract Numerous comparative clinical trials have been conducted evaluating combination hormonal therapy involving the aromatase inhibitor aminoglutethimide, but there is no evidence for any superiority of this approach over single-agent therapy alone. The advent of new aromatase inhibitors with greater potency, selectivity, and better tolerability has prompted a reconsideration of the combined therapy approach, with attention being focused on pharmacologic and endocrinologic clinical research. The value of combining newer aromatase inhibitors with other hormonal agents remains to be established.