We report on the design, development, and performance of a versatile and mobile fiber-optic based timeresolved fluorescence apparatus for in-vivo spectroscopy of biological tissues. The apparatus is of modular design which allows for facile interfacing with different pulsed light sources and fiber-optic probes. Main features of the apparatus include: 1) fast acquisition of fluorescence decays with high temporal resolution (0.3 ns) for a broad range of emission wavelengths (300 to 850 nm) and lifetimes (0.3 ns to ms), 2) near real time analysis of fluorescence decays via a Laguerre deconvolution technique, and 3) compatibility with the clinical environment (endoscopic procedures or other intraoperative uses). The apparatus is currently employed for in-vivo studies of diseased tissues (cardiovascular and oncological applications).