Investigations of indirect and direct actions of steroids on the mitochondria are relatively new areas of research. In this review we provide brief background information regarding mitochondrial structure and function and then focus upon interactions of glucocorticoid, estrogen, androgen, and progesterone receptors with mitochondria. We evaluate the current evidence for steroid receptor localization in the mitochondria based on techniques of Western blot analysis, immunocytochemistry, electron microscopy, and mass spectrometry. Steroid receptor-dependent interactions with mitochondria may include transcriptional regulation of nuclear DNA-encoded mitochondrial proteins, transcriptional regulation of mitochondrial DNA-encoded proteins, or indirect effects on mitochondria due to interactions with cytoplasmic signaling peptides and non-genomic control of cation fluxes. These interactions may play a role in mitochondrial-dependent processes of oxidative phosphorylation and apoptosis. Physiological examples of these interactions are discussed.