Mitochondrial calcium (Ca²⁺) signaling is crucial for cardiac homeostasis and disease. In healthy hearts, mitochondrial Ca²⁺ levels regulate oxidative metabolism to match ATP consumption. During ischemia/reperfusion (I/R) injury, excessive mitochondrial Ca²⁺ triggers the mitochondrial permeability transition pore (mPTP), leading to cell death. Modulating mitochondrial Ca²⁺ handling via the uniporter and sodium/calcium exchanger offers therapeutic potential for I/R injury. Mitochondria are central to energy production and cell death regulation. Ca²⁺ plays a key role in cardiac myocyte physiology, with mitochondrial Ca²⁺ signals adapting oxidative metabolism to ATP turnover. During I/R, mitochondrial Ca²⁺ overload induces mPTP opening, causing cell death. Therapeutic strategies targeting Ca²⁺ handling can prevent this. The mitochondrial Ca²⁺ uniporter (MCU) is essential for Ca²⁺ uptake, regulated by MICU1, which acts as a gatekeeper. MCUb, a paralog, can reduce Ca²⁺ uptake. NCLX facilitates Ca²⁺ extrusion, preventing overload. Modulating these pathways can protect against I/R injury. MICU1 regulation is critical for controlling Ca²⁺ flux. NCLX overexpression reduces superoxide and protects against I/R. Overall, mitochondrial Ca²⁺ handling is vital for cardiac protection, with strategies to modulate Ca²⁺ influx and efflux offering potential therapeutic approaches.Mitochondrial calcium (Ca²⁺) signaling is crucial for cardiac homeostasis and disease. In healthy hearts, mitochondrial Ca²⁺ levels regulate oxidative metabolism to match ATP consumption. During ischemia/reperfusion (I/R) injury, excessive mitochondrial Ca²⁺ triggers the mitochondrial permeability transition pore (mPTP), leading to cell death. Modulating mitochondrial Ca²⁺ handling via the uniporter and sodium/calcium exchanger offers therapeutic potential for I/R injury. Mitochondria are central to energy production and cell death regulation. Ca²⁺ plays a key role in cardiac myocyte physiology, with mitochondrial Ca²⁺ signals adapting oxidative metabolism to ATP turnover. During I/R, mitochondrial Ca²⁺ overload induces mPTP opening, causing cell death. Therapeutic strategies targeting Ca²⁺ handling can prevent this. The mitochondrial Ca²⁺ uniporter (MCU) is essential for Ca²⁺ uptake, regulated by MICU1, which acts as a gatekeeper. MCUb, a paralog, can reduce Ca²⁺ uptake. NCLX facilitates Ca²⁺ extrusion, preventing overload. Modulating these pathways can protect against I/R injury. MICU1 regulation is critical for controlling Ca²⁺ flux. NCLX overexpression reduces superoxide and protects against I/R. Overall, mitochondrial Ca²⁺ handling is vital for cardiac protection, with strategies to modulate Ca²⁺ influx and efflux offering potential therapeutic approaches.