INTRODUCTION: The hospital environment plays a role in the cross-transmission of multidrug-resistant bacteria. The aim of this study was to evaluate the bacterial contamination of the hospital environment during chronic wound dressing change. PATIENTS AND METHODS: This study was performed from July 2010 to May 2011. Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacteriaceae were counted in environmental samples (air and surfaces) that were obtained in the rooms of patients with wounds colonized (cases, n=9) or not (controls, n=15) during or not during wound dressing change. Bacterial contamination was compared to that found in the rooms of patients without colonized wounds. RESULTS: The environment was frequently contaminated during wound dressing change (38% of the sampled series were positive). In comparison, the contamination was less frequent in the environment of patients with colonized wounds when the wounds were not being dressed (14.3%) and in controls (3.8%). S. aureus was the most frequent species identified in positive samples. DISCUSSION: These results suggest that previously recommended measures such as hand hygiene after contact with the environment and wearing a mask are justified. Moreover, other measures should be suggested, in particular cleaning the room before and after dressing change of colonized wounds. LEVEL OF EVIDENCE: Level III: case control study.