Background Communication with patients receiving mechanical ventilation in an intensive care unit can be challenging. Once a patient is tracheostomized, a speaking valve may enable restoration of verbal communica-tion. To date, no data are available on the effect of speaking valves on communication success in intensive care units. Objective The aim of this prospective cohort study was to measure communication success before and during speaking valve use for intensive care patients being weaned from mechanical ventilation, from both the nurses’ and the patients’ perspectives. Methods In a prospective cohort study, consecutive eligible patients and their nurses were asked to com-plete newly developed questionnaires on communication success before and while patients used a speaking valve (6 questions for patients, 5 questions for nurses, answers on a 10-point scale with 10 the best score). The Wilcoxon signed rank test was used to analyze score differences. Results For all questionnaire items, both patients (n = 25) and nursing staff (n = 52) reported significantly higher communication success during speaking valve use. Nurses understood moderately well that their patients were in pain (median [IQR], 5.8 [4.7-7.4]) even before speaking valve use. Most patients found it challenging to say something quickly even while using a speaking valve (6.9 [5.7-10.0]). Overall, speaking valve use mark-edly increased communication success. Conclusion A speaking valve should be considered for patients with a tracheostomy as soon as possible toimprove their communication success.