Biosensor research is a rapidly expanding field with an immense market potential spanning a broad spectrum of applications including biomedical diagnostics, environmental monitoring, veterinary and food quality control. Porous silicon (pSi) is a nanostructured material poised to take centre stage in the biosensor development effort. This can be ascribed to the ease and speed of fabrication, remarkable optical and morphological properties of the material (including tuneable pore size and porosity), large internal surface area and the versatile surface chemistry. The past decade has, therefore, seen diverse proof-of-principle studies involving pSi-based optical and electrochemical transducers, which are highlighted here. We also provide comparative analysis of transducer sensitivity, robustness and susceptibility to interferences and cover strategies for sensitivity enhancement by means of signal amplification.