We enrolled 42 patients with nonseptic olecranon bursitis in a double-blind prospective treatment trial to compare the efficacy of an intrabursal steroid preparation with that of an oral anti-inflammatory agent. Patients were randomized into one of four treatment regimens: (1) methylprednisolone acetate (20 mg) intrabursal injection and oral naproxen (1 g/d for 10 days), (2) methylprednisolone acetate (20 mg) intrabursal injection and oral placebo for 10 days, (3) oral naproxen (1 g/d for 10 days), and (4) oral placebo for 10 days. The degree of swelling in millimeters was assessed at study introduction and at 1, 3, and 6 weeks. At 6 months, the number of patients requiring reaspiration for bursitis recurrence was tabulated. Data at 1 week indicated that patients treated with an intrabursal methylprednisolone acetate injection (20 mg) demonstrated the most rapid decrease in swelling. At 6 weeks, the methylprednisolone-treated groups demonstrated sustained improvement. At 6 months, the mean number of reaspirations per patient for reaccumulation of bursal fluid was higher in groups 3 (1.0 +/- 1.2) and 4 (0.4 +/- 0.7). An intrabursal methylprednisolone acetate 20-mg injection seems to be the most effective treatment regimen for nonseptic olecranon bursitis.