The aim of this paper is to provide a comprehensive overview of biometrics as a recognition technology based on the physiological and behavioral characteristics of individuals and to investigate its impact on data protection and privacy. The paper begins with a definition and description of the development of biometrics, emphasizing its importance throughout history and in the modern digital age. Key biometric methods such as fingerprinting, eye scanning, facial geometry, face and body thermogram, DNA analysis, voice analysis, and handwriting and signature analysis are then described in detail. Each of these methods is explained through their basic principles, advantages and disadvantages, with special emphasis on practical application and security challenges. After that, the paper deals with biometric identification and processing of biometric data, exploring how such data is collected, stored, processed and used for user authentication and identification. Then the functionality of the biometric system is explained and the threats that can undermine its security are listed. Data protection and privacy are central topics in the last part of the paper, where legislative frameworks such as the General Data Protection Regulation (GDPR) are discussed. It also states the measures that need to be taken to protect information systems in general. Finally, the paper provides concluding considerations on ethical issues and the future of biometrics in the context of technology development and privacy protection.