Background The treatment of pressure ulcers is complicated, given the various wound dressing products available. The cost of different treatments varies and the cost-effectiveness of each product has not been thoroughly evaluated. We compare two wound dressing protocols-alginate silver dressing (AlSD) and silver zinc sulfadiazine cream (AgZnSD) with regard to wound healing and cost-effectiveness Methods Patients with grade III or IV sacral or trochanteric pressure ulcers were eligible for this prospective, randomized controlled trial. The patients were randomized to receive one of the two dressings for an eight-week period. The criteria of efficacy were based on the Pressure Ulcer Scale for Healing (PUSH) scoring tool. The cost of treatment was also assessed. Results Twenty patients (12 women and 8 men) were randomly assigned to receive either AlSD (n=10) or AgZnSD cream (n=10). The demographic data and wound characteristics were comparable in the two groups. The two groups showed no significant difference in the reduction of PUSH score, wound size, or volume of exudate. The tissue type score was significantly lower in the AlSD group ($3.15{pm}0.68-1.85{pm}0.68$ vs. $2.73{pm}0.79-2.2{pm}0.41$; P=0.015). The cost of treatment was significantly lower in the AlSD group (377.17 vs. 467.74 USD, respectively; P<0.0001). Conclusions Alginate silver dressing could be effectively used in the treatment of grade III and IV pressure ulcers. It can improve wound tissue characteristics and is cost-effective.