We have synthesized Mn-doped CdS nanocrystals (NCs) with size ranging from 1.8-3 nm. Photo-luminescence (PL) spectra of the doped NCs differ from that of the undoped NCs with an additional peak due to Mn d-d transitions. Electron paramagnetic resonance spectra along with X-ray absorption spectroscopy and PL spectra confirm the incorporation of Mn in the CdS lattice. The fact that emissions from surface states and the Mn d levels occur at two different energies, allowed us to study the PL lifetime decay behaviour of both kinds of emissions. {\textcopyright} Indian Academy of Sciences.