Biomarker detection with very high sensitivity is an important requisite for clinical disease diagnosis. Though these markers help to diagnose the onset of the disease, their levels are often too low at the initial stages of disease progression. Nanotechnology has emerged as a potential field of research in the development of several novel biosensors to detect accurately very low levels of such biomarkers. Several types of nanomaterials, based on their size, shape, surface characteristics, etc., have been utilized in the design and development of novel biosensors for the detection of various biomarkers for an effective point-of-care and onsite diagnosis. With the aid of nanotechnology, these point-of-care devices can also be miniaturized rendering a portable detection nanodevice fabrication with comparable sensitivity to that of the conventional sophisticated instruments. This chapter provides insight and overview of Nanobiosensor, which will reflect the information about various technologies, types of materials being used, and a wider range of applications in disease diagnosis. Eventually, we utilize numerous examples from different literature and research groups to provide an explicit view of each section. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.