This study compared wound healing efficacy of two silver dressings, AQUACEL(®) Ag and Urgotul(®) Silver, against venous ulcers at risk of infection, over 8 weeks of treatment. The primary objective was to show non inferiority of AQUACEL(®) Ag to Urgotul(®) Silver. Patients (281) were randomised into two groups. The AQUACEL(®) Ag group had 145 patients treated with AQUACEL(®) Ag for 4 weeks followed by AQUACEL for another 4 weeks. TheUrgotul(®) Silver group had 136 patients treated with Urgotul(®) Silver for 4 weeks followed by Urgotul(®) for another 4 weeks. In both groups, ulcer size and depth, safety events and ulcer healing were compared. After 8 weeks of treatment, the AQUACEL(®) Ag group had a relative wound size reduction (49·65% ± 52·53%) compared with the Urgotul(®) Silver group (42·81% ± 60·0%). The non inferiority of the AQUACEL(®) Ag group to the Urgotul(®) Silver group was established based on the difference between them (6·84% ± 56·3%, 95% confidence interval -6·56 to 20·2) and the pre-defined non inferiority margin (-15%). Composite wound healing analysis showed that the AQUACEL(®) Ag group had statistically higher percentage of subjects with better wound progression (66·9% versus 51·9%, P = 0·0108). In general, both dressings were effective at promoting healing of venous ulcers.