BACKGROUND Topical diclofenac diethylamine (DDEA) 2.32% gel achieves lasting efficacy in localized pain with two applications per day, while maintaining the favorable safety profile of topical diclofenac and potentially improving convenience and patient compliance. METHODS This randomized double-blind controlled study enrolled patients with acute ankle sprain treated with DDEA 2.32% gel two times per day (bid) (n = 80) or three times per day (tid) (n = 80) or placebo (n = 82). Efficacy (including pain and swelling) and local tolerability were evaluated during 8 ± 1 d. RESULTS By day 5, the reduction in pain on movement (POM) (primary efficacy variable) with DDEA bid and tid (49.1 and 49.7 mm, respectively; 100-mm visual analog scale) was almost double that with placebo (25.4 mm) (P < 0.0001). In patients with severe baseline POM (≥ 80 mm), mean change in POM from baseline to day 5 with DDEA bid or tid was 30-40 mm greater than that with placebo, which was double the difference (15-20 mm) in patients with mild-moderate baseline POM (<80 mm). More than 70% of all DDEA patients experienced ≥ 50% reduction in POM between days 1 and 5 versus 21% of placebo patients (P < 0.0001). By study end (day 8), ankle swelling in patients treated with DDEA (0.3 cm) was one-third that in those treated with placebo (0.9 cm) (P < 0.0001), which had still not achieved the level of ankle joint function seen with DDEA on day 5 (P < 0.0001). At day 5, treatment satisfaction was "good" to "excellent" in almost 90% of DDEA patients but only "good" or "very good" in 23% of placebo patients (P < 0.0001). DDEA 2.32% gel was well tolerated. CONCLUSIONS DDEA 2.32% gel twice daily (applied in the morning and evening) was well tolerated and provided lasting relief from pain, improved function, and reduced symptomatic healing time in uncomplicated ankle sprain.