Precision medicine represents a transformative approach to healthcare that tailors disease prevention, diagnosis, and treatment according to individual genetic, environmental, lifestyle, and clinical characteristics. Unlike traditional one-size-fits-all medical models, precision medicine utilizes genomic technologies, biomarker analysis, artificial intelligence, big data analytics, and advanced diagnostics to deliver personalized interventions. The integration of genomic sequencing, pharmacogenomics, digital health technologies, and predictive analytics has significantly improved outcomes in oncology, cardiovascular diseases, rare genetic disorders, infectious diseases, and chronic illnesses. This review examines the principles, technologies, clinical applications, benefits, challenges, ethical considerations, and future directions of precision medicine and personalized healthcare. The findings highlight the growing importance of individualized care in improving healthcare quality, treatment effectiveness, and patient outcomes.