OBJECTIVES: Systematic analysis of the available studies of the clinical effectiveness and safety of negative pressure therapy, as compared with traditional courses of treatment, in complex foot wounds in diabetic patients.  METHODS: A bibliographical search was performed in the following databases: Embase.com, Medline and Cochrane Library, covering from 2000 until the present. The following descriptors and key words were used: diabetic foot, negative-pressure wound, vacuum-assisted closure and diabetic ulcers. The Jaddad criteria were used to determine the quality of the clinical trials.  The studies selected were randomized clinical trials that featured patients older tan 18 years, with complex ulcers, postoperative wounds, or wounds resulting from the amputation of the foot, with a control group comparing negative pressure therapy with conventional therapies (saline solution, alginates or hydrophilic substances. The treatments were applied every 48 hours. A total of 12 studies, of which only 7 were pertinent, were selected. Two independent reviewers extracted the information and determined the methodological quality of the selected studies.  RESULTS: Of the 7 studies selected (539 patients), 5 involved patients with postoperative wounds and 2 used the same group of patients.  One of the two studies involving ulcers of the foot was limited by its simple size (N=10). The methodological quality of the studies is moderate-low. CONCLUSIONS: The evidence supports the effectiveness and security of negative pressure wound therapy in complex foot ulcers in diabetic patients. Given that it is unlikely that further research will change this positive appraisal (despite the moderate-low quality of the studies analyzed, its cost profile and the absence of adverse effects) it is possible to make a strong recommendation in favor of the therapy.