It has been reported that rapid thermal annealing of implanted (Be and Si) InSb at a temperature range of 300–450 °C for 20 s is sufficient to activate the implanted dopants. To investigate the effect of such annealing on the unimplanted parts of InSb, the electrical properties of Al and Ag/n‐InSb in which InSb is rapidly annealed (using proximity method) prior to Al and Ag evaporation are analyzed. It was determined that annealing at 300 and 350 °C does not degrade contact properties. The parameters of contacts considered here were barrier height (determined using capacitance–voltage method and current–voltage method) and ideality factor. For unannealed contacts the value of barrier height and ideality factor were found to vary in the range 0.14–0.17 eV and 1.12–1.31, respectively, depending on the metal type. Annealing at 400 °C slightly degraded the contact properties while annealing at 450 °C caused a significant degradation. The barrier height and ideality factor decreased to 0.1 eV and 1.41–1.52, respectively, when contacts are annealed at 450 °C. Creation of nonstoichiometric InSb surface layer and injection of charges into native oxide layer are likely causes for the contact degradation.