BACKGROUND: Considerable evidence supports corticosteroid injection as an effective treatment for trigger finger. One common side effect, the flare reaction, is a well-documented phenomenon of increased pain following steroid injections. Its incidence and intensity may be related to steroid composition. The purpose of this study was to determine whether betamethasone and methylprednisolone injections for trigger fingers have differing intensity of pain or incidence flare reaction. METHODS: Patients with symptomatic trigger finger were recruited during their hand surgery visits. Patients were randomized into 2 treatment groups: betamethasone (40 mg) and methylprednisolone (6 mg) mixed with lidocaine 1%. Treatment group assignment was blinded to the patients and investigators. Visual analog scale pain measurements were taken prior to injection, 5 minutes postinjection, and daily thereafter for 7 days. RESULTS: Sixty-four patients were randomized into the 2 treatment groups. Patients in the betamethasone group reported slightly higher baseline pain compared with the methylprednisolone group, but lower pain on day 1. None of the following days showed a statistically significant difference. CONCLUSIONS: The incidence of flare and severe flare reactions of betamethasone injections for trigger finger management was roughly double that of methylprednisolone, but this difference was not statistically significant. Further studies are required to evaluate the relative course of nonflare postinjection pain for different corticosteroid injections for trigger finger injections.