Holmium borohydride, Ho(BH4)(3), its composites with LiBH4, and a mixed-cation derivative, K[Ho(BH4)(4)], have been prepared via mechanochemical reaction between HoCl3, LiBH4 (and also KBH4 in case of K[Ho(BH4)(4)]). These compounds are isostructural to the related rare earth borohydrides, adopting alpha-Y(BH4)(3), beta-Y(BH4)(3), and Na[Sc(BH4)(4)]-type structures, respectively. The relative amount of alpha-Ho(BR4)(3) and beta-Ho(BH4)(3) can be controlled by the composition of reagents. While beta-Ho(BH4)(3) has not been obtained from stoichiometric mixtures of HoCl3 and LiBH4, the excess of LiBH4 favours it as the main product. Thermal decomposition of alpha-Ho(BH4)(3), as well as K[Ho(BH4)(4)] commences above 170 degrees C, with the fastest rate within 250-260 degrees C, which is slightly lower than for the corresponding boro-hydrides of yttrium. LiBH4 is destabilised thermally in the composites with beta-Ho(BH4)(3), which leads to desorption of >40% total amount of H, below 450 degrees C, while in case of pure LiBH4 only <20% total amount of H-2 is released in these conditions. The catalytic mechanism is as yet unknown. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.