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In this study, iron sulfate (FeSO 4) and sodium borohydride (NaBH 4) were used to synthesize Fe-Fe 2 B nanocrystals via the solvothermal route. Synthesis of Fe-Fe 2 B nanocrystals was carried out under Argon (Ar) gas atmosphere with aqueous solutions of FeSO 4 .7H 2 O and NaBH 4 at various concentrations and reaction time. The phases and microstructures of nanocrystals thus formed were characterized by X-Ray diffraction (XRD) spectroscopy and scanning electron microscopy (SEM). Surface areas of nanocrystals were measured by a surface area and pore-size analyzer using nitrogen adsorption-desorption method together with Brunauer-Emmett-Teller (BET) equation. The vacuum dried nanoparticles were calcined under both Ar and air at 500 ºC. Nano-cylindrical structures of Fe-Fe 2 B were observed when calcinated under Ar atmosphere; whereas more irregular shaped particles were noticed when calcinated under air. The surface areas of Fe-Fe 2 B were determined as 12 m 2 /g, 5.5 m 2 /g and 16.5 m 2 /g, for vacuum dried, Ar-calcined and O 2-calcined products respectively. The catalytic effect of those nano-particles to generate hydrogen was studied by determining reaction rate of decomposition of NaBH 4 in aqueous alkaline solution. The catalytic activity was investigated by systematic variation of three parameters (1) the amount of Fe-Fe 2 B, (2) the concentration of NaBH 4 and (3) the concentration of NaOH. The effect of temperature on the catalytic activity was also studied separately for the most effective composition by varying the temperature from 25 to 70 °C. It was noticed that the catalytic activity of vacuum dried nanocrystals was the highest. The catalytic activity was found to increase with the increase in NaBH 4 concentration and decrease with the increase in NaOH concentration. The influence of temperature studied with 0.01 g of Fe-Fe 2 B in 1 % w/w NaBH 4 solution showed that the rate of hydrogen generation could be increased almost 5 times more by varying the temperature from 25 °C to 70 °C.