The article provides an overview of glucose biosensors in clinical practice, highlighting their historical development, basic principles, analytical performance, and current status. Blood glucose monitoring is crucial for diabetes management, and various glucose biosensors have been developed to meet this need. The first glucose biosensor was introduced in 1962, and since then, significant advancements have been made, leading to the dominance of glucose biosensors in the market. These sensors are primarily electrochemical, using enzymes like glucose oxidase (GOx) or glucose dehydrogenase (GDH) to convert glucose into hydrogen peroxide, which is then measured. The article discusses the evolution of glucose biosensors from first-generation devices based on oxygen substrates to second-generation devices using redox mediators, and finally, third-generation devices that do not require mediators. Continuous glucose monitoring systems (CGMS) and non-invasive glucose monitoring systems are also reviewed, along with their limitations and challenges. The importance of analytical performance validation, including precision, accuracy, linearity, and user performance, is emphasized. Despite these advancements, reliable glucose monitoring still faces challenges, and further improvements in technical performance, standardization, and user training are necessary.The article provides an overview of glucose biosensors in clinical practice, highlighting their historical development, basic principles, analytical performance, and current status. Blood glucose monitoring is crucial for diabetes management, and various glucose biosensors have been developed to meet this need. The first glucose biosensor was introduced in 1962, and since then, significant advancements have been made, leading to the dominance of glucose biosensors in the market. These sensors are primarily electrochemical, using enzymes like glucose oxidase (GOx) or glucose dehydrogenase (GDH) to convert glucose into hydrogen peroxide, which is then measured. The article discusses the evolution of glucose biosensors from first-generation devices based on oxygen substrates to second-generation devices using redox mediators, and finally, third-generation devices that do not require mediators. Continuous glucose monitoring systems (CGMS) and non-invasive glucose monitoring systems are also reviewed, along with their limitations and challenges. The importance of analytical performance validation, including precision, accuracy, linearity, and user performance, is emphasized. Despite these advancements, reliable glucose monitoring still faces challenges, and further improvements in technical performance, standardization, and user training are necessary.