INTRODUCTION : Successful communication between staff and patients plays a key role in the well-being of critically ill patients within an intensive care unit. The use of augmentative and alternative communication strategies could contribute to better pain management, medical outcomes and shorter hospital stays for patients in critical care units. OBJECTIVE : To describe healthcare professionals’ use of augmentative and alternative communication strategies to communicate with critically ill patients regarding pain in an intensive care unit. RESEARCH METHOD : A quantitative approach was used, and 83 healthcare professionals of different professions responded to a survey consisting of 16 items that focused on their knowledge of and access to augmentative and alternative communication strategies. The results are presented as descriptive and comparative non-parametric statistics. SETTING : The setting of the study was an intensive care unit in a Swedish hospital. RESULTS : All participants had experience of working in intensive care units with patients with communication challenges. Knowledge of augmentative and alternative communication tools differed between the professions, and less experienced healthcare professionals tended to administer sedative drugs more often than more experienced healthcare professionals. CONCLUSION : Healthcare professionals work with vulnerable patients on a daily basis. Their knowledge of communication tools and clinical experience may influence how they communicate and treat pain in patients in intensive care units.