We report our investigations done on TiMn 1 . 5 intermetallics in relation to hydrogen storage behaviour. TiMn 1 . 5 is known to exhibit the clear plateau in the series TiMn 2 - x (x=0-1.25). This communication describes the synthesis of TiMn 1 . 5 by using r.f. induction furnace and characterization by employing, X-ray diffractometry, transmission electron microscopy and Sievert's apparatus for hydrogen desorption characteristics. The correlation between the microstructural characteristics and the hydrogenation behaviour for TiMn 1 . 5 is discussed. The clarity of the plateau pressure is supported by the occurrence of ordered superstructure in the partially hydrogenated sample. The superstructure has the periodicity a m o d =(8/3)a p a r e n t . Electron micrographs of the hydrogenated samples at successive stages showed dendritic rupturing of the as-synthesized TiMn 1 . 5 . A model has been proposed to explain the stability and hydrogenation behaviour of TiMn 1 . 5 with a modified structure in which Ti atoms substitute for Mn vacancy and at the same time softens the void to accommodate hydrogen.