It has been reported that rapid thermal annealing of implanted (Be and Si) InSb at a temperature range of 300-450 degrees 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 degrees 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 degrees C slightly degraded the contact properties while annealing at 450 degrees 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 degrees C. Creation of nonstoichiometric InSb surface layer and injection of charges into native oxide layer are likely causes for the contact degradation.