BACKGROUND: Foot ulcers in people with diabetes mellitus are a common and serious global health issue. Dressings form a key part of ulcer treatment, with clinicians and patients having many different types to choose from including alginate dressings. A clear and current overview of current evidence is required to facilitate decision-making regarding dressing use. OBJECTIVES: To compare the effects of alginate wound dressings with no wound dressing or alternative dressings on the healing of foot ulcers in people with diabetes mellitus. SEARCH METHODS: We searched The Cochrane Wounds Group Specialised Register (searched 4 January 2012); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4); Ovid MEDLINE (1950 to December Week 3 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, January 03, 2012); Ovid EMBASE (1980 to 2011 Week 52); and EBSCO CINAHL (1982 to 30 December 2011). There were no restrictions based on language or date of publication. SELECTION CRITERIA: Published or unpublished randomised controlled trials (RCTs) that have compared the effects on ulcer healing of alginate dressings with alternative wound dressings or no dressing in the treatment of foot ulcers in people with diabetes. DATA COLLECTION AND ANALYSIS: Two review authors independently performed study selection, risk of bias assessment and data extraction. MAIN RESULTS: We included six studies (375 participants) in this review; these compared alginate dressings with basic wound contact dressings, foam dressings and a silver-containing, fibrous-hydrocolloid dressing. Meta analysis of two studies found no statistically significant difference between alginate dressings and basic wound contact dressings: risk ratio (RR) 1.09 (95% CI 0.66 to 1.80). Pooled data from two studies comparing alginate dressings with foam dressings found no statistically significant difference in ulcer healing (RR 0.67, 95% CI 0.41 to 1.08). There was no statistically significant difference in the number of diabetic foot ulcers healed when an anti-microbial (silver) hydrocolloid dressing was compared with a standard alginate dressing (RR 1.40, 95% CI 0.79 to 2.47). All studies had short follow-up times (six to 12 weeks), and small sample sizes. AUTHORS' CONCLUSIONS: Currently there is no research evidence to suggest that alginate wound dressings are more effective in healing foot ulcers in people with diabetes than other types of dressing however many trials in this field are very small. Decision makers may wish to consider aspects such as dressing cost and the wound management properties offered by each dressing type e.g. exudate management.