The unique properties of nickel-titanium (NiTi) alloy, such as its shape memory effect, super-elasticity and biocompatibility, make it ideal material in various fields such as aerospace and automotive industries, micro-electronics and medical devices. In this regard, joining of this material to itself and to other materials is of considerable importance, and great attention has been given to it during past few years. Stainless steels are one of the dominant materials which are widely used in different applications especially in medical devices owing to their mechanical properties, workability, low cost and corrosion resistance. Therefore, joining of NiTi to stainless steel would be desirable for widening of its applications. Due to the low and precise heat input, low energy density, small fusion and heat affected zones, low residual stress, low weld distortion and high welding speed, laser welding is a suitable technique to join NiTi alloy. Hence, in this work, a comparative study on Nd:YAG laser welding of NiTi wire to itself and to AISI 304 stainless steel wire has been made. Moreover, to provide some foundation for improving the properties of the dissimilar laser welded NiTi-stainless steel wires joint, the effect of post-weld heat treatments on the joint properties of the dissimilar joint has been investigated. Microstructures, phase transformation behavior and mechanical properties of the laser joints were investigated using optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC), vickers microhardness (HV 0.2 ) and tensile testing techniques. Corrosion behavior of weldments in the Ringer’s physiological solution at 37 ?C was also investigated using open circuit potential, potentiodynamic polarization and immersion tests. Results indicated that the tensile strength of similar NiTi laser joint was 835 MPa (about 63% of the tensile strength of the as-received NiTi wire) with rupture strain of about 16%. This joint also possessed the superelastic property and enabled the possibility to benefit from the pseudo-elastic behavior of the NiTi component. However, tensile strength and strain decreased significantly after dissimilar laser welding of NiTi to stainless steel due to the formation of brittle intermetallic compounds in the weld zone during laser welding. In addition, for the similar laser joint, corrosion resistance of the weld metal was better than that of the base metal. On the other hand, for the dissimilar laser joint, the weld metal exhibited remarkable corrosion resistance which was close to the corrosion resistance of the stainless steel and better than that of the NiTi. Also, post-weld heat treatments of laser welded NiTi shape memory alloy to stainless steel wire showed remarkable effects on mechanical properties and corrosion behavior of the welded wires. Post-weld heat treatment at 200 ?C increased corrosion resistance and tensile strength of the joint up to ~1.8 times that of the as-weld, with no heat treatment, joint. Post-weld heat treatment at 400 ?C, on the contrary, deteriorated the mechanical properties and corrosion behavior mainly due to precipitation of newly made intermetallic compounds in the weld zone. The conclusion was that the post-weld heat treatment temperature must critically be controlled in order to improve the properties of the laser welded dissimilar NiTi-stainless steel joint. Keywords: NiTi shape memory alloy, Stainless steel, Laser welding, Post-weld heat treatment.