Spherical Fe71-Co29 nanocrystals functionalized by trisodium citrate (TSC) have been synthesized using co-precipitation process. The synthesized nanocrystals have disordered structure, reductive hydrogen annealing at 450 °C has transformed the disordered phase to body centered cubic phase (CsCl structure) without secondary phases which was subsequently authenticated using Rietveld refinement technique. The TSC adhere with the Fe-Co nanocrystal's surface by carboxylate chemisorption which has been confirmed using FT-IR spectroscopy. Back scattered electron microscope image confirms the spherical morphology with size around 20 nm. The observed saturation magnetization is as large as 95.6% of bulk (242 emu g-1) which is a significant indication for the crystallization of single phase Fe 71-Co29 nanocrystals. © 2011 Elsevier B.V.