Porous silicon (PSi) has emerged over the past decade as a promising biomaterial for nanomedicine in general and cancer nanomedicine in particular. PSi offers a unique combination of properties, including large surface area and porous volume, biocompatibility, degradability in vivo into non-toxic silicic acid species, as well as its wealth of intrinsic optical properties (e.g., luminescence, photonic). This arsenal of properties together with the ability to tailor the PSi nanostructure and surface characteristics have led to an immense research effort directed at the development of PSi-based platforms for biomedical applications. After a brief introduction of the biology of cancer and currently practiced therapies, we provide an updated review of the progress of PSi-based platforms for cancer therapy and imaging.