A ketosteroid, or an oxosteroid, is a steroid in which a hydrogen atom has been replaced with a ketone (C=O) group.

A 17-ketosteroid is a ketosteroid in which the ketone is located specifically at the C17 position (in the upper right corner of most structure diagrams).

Examples of 17-ketosteroids include:

• Androstenedione
• Androstanedione
• Androsterone
• Dehydroepiandrosterone
• Epiandrosterone
• Epietiocholanolone
• Etiocholanolone

17-Ketosteroids are endogenous steroid hormones.

• Hydroxysteroid
• Hydroxysteroid dehydrogenase

• 17-Ketosteroids at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
• MedlinePlus Encyclopedia: 003460