110 patients with knee osteoarthritis were randomized to a single injection of either hyaluronic acid (Hylan G-F 20) or corticosteroid (triamcinolone acetonide). The purpose of this study was to compare pain scores and results on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) between the two groups over a 6-month follow-up. Results demonstrated significant differences in favour of the corticosteroid group compared to the hyaluronic acid group for pain scores within the first week of follow-up and WOMAC scores within the first 2 weeks of follow-up. Differences between groups at all other time points up to 6 months were not significant.