Mitochondria are semi-autonomous organelles crucial for cellular energy metabolism and various physiological processes. They play a central role in energy production through oxidative phosphorylation, as well as in other metabolic activities such as the electron transport chain, citric acid cycle, and fatty acid oxidation. Mitochondrial dysfunction is implicated in a wide range of diseases, including aging, diabetes, Parkinson's disease, and cancer. The article provides an overview of the mechanisms by which mitochondria contribute to these diseases and highlights new insights into their involvement in both disorders and health maintenance. Key topics include the structure and function of mitochondria, oxidative phosphorylation, mtDNA mutations, nuclear DNA (nDNA) mutations, mitochondrial dynamics, mitophagy, mitochondrial biogenesis, reactive oxygen species (ROS), and the role of mitochondria in neurodegenerative, cardiovascular, and metabolic diseases. The article also discusses therapeutic approaches targeting mitochondrial dysfunction, emphasizing the importance of understanding mitochondrial structure and function for developing targeted therapies.Mitochondria are semi-autonomous organelles crucial for cellular energy metabolism and various physiological processes. They play a central role in energy production through oxidative phosphorylation, as well as in other metabolic activities such as the electron transport chain, citric acid cycle, and fatty acid oxidation. Mitochondrial dysfunction is implicated in a wide range of diseases, including aging, diabetes, Parkinson's disease, and cancer. The article provides an overview of the mechanisms by which mitochondria contribute to these diseases and highlights new insights into their involvement in both disorders and health maintenance. Key topics include the structure and function of mitochondria, oxidative phosphorylation, mtDNA mutations, nuclear DNA (nDNA) mutations, mitochondrial dynamics, mitophagy, mitochondrial biogenesis, reactive oxygen species (ROS), and the role of mitochondria in neurodegenerative, cardiovascular, and metabolic diseases. The article also discusses therapeutic approaches targeting mitochondrial dysfunction, emphasizing the importance of understanding mitochondrial structure and function for developing targeted therapies.