A prospective, randomized, double-blind study of 56 patients presenting with an overuse sports injury was undertaken in order to compare the effect of a long-acting anesthetic (bupivacaine) with a short-acting anesthetic (lidocaine) in local corticosteroid injections. At presentation, patients were either administered a periarticular injection of 2 ml of methyl prednisolone acetate with bupivacaine (MPA-B) (40 mgs per ml + 5 mgs per ml) or 2 ml of MPA with lidocaine (MPA-L) (40 mgs per ml + 10 mgs per ml). No other treatment was given. Results indicated that pain inhibition was better in the MPA-B group during the first six hours after the injection, obviously because of the longer half-life of bupivacaine. In later evaluations no differences could be observed: in both groups pain disappeared partly or completely in two-thirds of the patients and full recovery to sports was possible in half of them. Long-acting bupivacaine is recommended as an anesthetic substance in local steroid injections of musculoskeletal overuse injuries.