Real-time monitoring and assessment of soil health is critical for early detection of changes in soil physical, chemical, and biological conditions, enabling informed decision-making and implementation of suitable measures at the right time to improve soil quality and crop productivity. This chapter explores multiple factors that contribute to soil degradation. More specifically, it focuses on the detection of soil physical parameters, pathogens, and contaminants such as pesticides and heavy metals that deteriorate soil fertility. Additionally, human exposure to the toxic chemical pollutants present in soil poses potential health risks. Hence, effective assessment of soil health is critical to maintain ecosystem sustainability. Early detection of soil conditions also enables the development of precision farming and smart agricultural systems. Conventional analytical techniques are widely used for their high sensitivity and efficiency, but their high cost, complex sample preparation, and limited portability due to the large size of equipment limit their applicability for real-time monitoring of soil health. With technological progression, nanobiosensors have emerged as transformative tools for the precise monitoring of soil health in terms of pH, temperature, moisture, nutrients, pathogens, toxic gases, and soil contaminants. The integration of nanomaterials into biosensors enhances their selectivity, reproducibility, and sensitivity at the nanoscale. Nanoparticles (NPs) also improve the interaction of biosensors with target molecules, due to their high reactivity, small size, and large surface-to-volume ratio. Nanobiosensors are eco-friendly, biocompatible, highly sensitive, and portable with ease of use at different sites for real-time assessment. This chapter also reviews various types of nanobiosensors that have been reported in literature, highlighting their design and applications in the assessment of soil health.