Realizing high-power long-duration discharges puts specific constraints on diagnostics: Their front parts have to withstand important thermal loads, eventually requiring active cooling of critical parts, and drifts in measurements have to be avoided in order to supply reliable measurement during the whole discharge duration. Furthermore, the importance of diagnostics for missions other than physics understanding, such as machine operation or safety control, increases. The diagnostics system of Tore Supra consists of roughly 30 diagnostics, covering a large range of plasma parameters from the core to the edge. They have been designed for long-duration plasma discharges, which can last up to 1000 s. Their inner components have been dimensioned to endure continuous high-radiation fluxes, and most of them have been conceived to give a fair measurement all along the discharges.