Background: It is now well documented that critically ill patients are ă exposed to stressful conditions and experience discomforts from multiple ă sources. Improved identification of the discomforts of patients in ă intensive care units (ICUs) may have implications for managing their ă care, including consideration of ethical issues, and may assist ă clinicians in choosing the most appropriate interventions. The primary ă objective of this study was to assess the effectiveness of a ă multicomponent program of discomfort reduction in critically ill ă patients. The secondary objectives were to assess the sustainability of ă the impact of the program and the potential seasonality effect. ă Methods/design: We conducted a multicenter, cluster-randomized, ă controlled, single (patient)-blind study involving 34 French adult ICUs. ă The experimental intervention was a 6-month period during which the ă multicomponent program was implemented in the ICU and included the ă following steps: identification of discomforts, immediate feedback to ă the healthcare team, and implementation of targeted interventions. The ă control intervention was a 6-month period during which any program was ă implemented. The primary endpoint was the monthly overall score of ă self-reported discomfort from the French questionnaire on discomforts in ă ICU patients (IPREA). The secondary endpoints were the scores of the ă discomfort items of IPREA. The sample size was 660 individuals to obtain ă 80 % power to detect a 25 % difference in the overall discomfort score ă of IPREA between the two groups (design effect: 2.9). ă Discussion: The results of this cluster-randomized controlled study are ă expected to confirm that a multicomponent program of discomfort ă reduction may be a new strategy in the management of care for critically ă ill patients.