Phosphorus is required for plants and humans to survive because it is needed for cell signaling, skeletal integrity, energy storage and metabolism. Phosphorus measurements are performed using colorimetric and electrochemical methods. Colorimetry is the most accepted method for commercial devices for phosphorus monitoring while electrochemical systems are still in the research phase. Here we provide the first comprehensive review of solid-state sensors for phosphate monitoring. The review focuses on solid state reagent storage for colorimetric sensors and different materials used in solid state electrochemical sensors. The electrochemical sensors are further classified into three groups: potentiometric, amperometric and voltammetric. All sensors are evaluated based on parameters such as measurement range, limit of detection (LOD), working pH and response time. Finally, we discuss limitations of the current sensors and future directions for the development of these sensors.