Transient liquid phase (TLP) bonding of Ni-24 at % Al-16 at%Cr and Ni-30 at% Al with a tetragonal L1(0) type martensitic microstructure to nominally stoichiometric NiTi with a monoclinic (distorted B19 type) martensitic matrix is investigated in this paper. The TLP bonds described in this article employed 50 Ccm thick copper interlayers. Bonds were prepared using holding times of between 20 min and 2 h at a bonding temperature of 1150 degrees C. A holding time of 1 h at 1150 degrees C was sufficient to remove the liquid-phase from the bond-line, however a layer of Ni2AlTi (L2(1) type Heusler phase) was left : at the bond line. This layer remained present with further holding up to 2 h at 1150 degrees C. With 50 mu m thick copper interlayers, 2 h holding at 1150 degrees C resulted in significant titanium diffusion, from the NiTi substrate, to the joint. Depletion of titanium from the NiTi substrate, in turn, reduced the solidus temperature of the NiTi substrate to the point where localized melting occurred on the surface of the NiTi substrate. Extensive microstructural changes were observed in the NiTi substrate after TLP bonding and these are discussed in detail. In contrast, the NiAl substrate was largely unchanged after TLP bonding.