The quality standards of the Dutch Society of Intensive Care require monitoring of the satisfaction of patientâ??s relatives with respect to care. Currently, no suitable instrument is available in the Netherlands to measure this. This study describes the development and psychometric evaluation of the questionnaire-based Consumer Quality Index â??Relatives in Intensive Care Unitâ?? (CQI â??R-ICUâ??). The CQI â??R-ICUâ?? measures the perceived quality of care from the perspective of patientsâ?? relatives, and identifies aspects of care that need improvement. The CQI â??R-ICUâ?? was developed using a mixed method design. Items were based on quality of care aspects from earlier studies and from focus group interviews with patientsâ?? relatives. The time period for the data collection of the psychometric evaluation was from October 2011 until July 2012. Relatives of adult intensive care patients in one university hospital and five general hospitals in the Netherlands were approached to participate. Psychometric evaluation included item analysis, inter-item analysis, and factor analysis. Twelve aspects were noted as being indicators of quality of care, and were subsequently selected for the questionnaireâ??s vocabulary. The response rate of patientsâ?? relatives was 81% (nâ??=â??455). Quality of care was represented by two clusters, each showing a high reliability: â??Communicationâ?? (Î±â??=â??.80) and â??Participationâ?? (Î±â??=â??.84). Relatives ranked the following aspects for quality of care as most important: no conflicting information, information from doctors and nurses is comprehensive, and health professionals take patientsâ?? relatives seriously. The least important care aspects were: need for contact with peers, nuisance, and contact with a spiritual counsellor. Aspects that needed the most urgent improvement (highest quality improvement scores) were: information about how relatives can contribute to the care of the patient, information about the use of meal-facilities in the hospital, and involvement in decision-making on the medical treatment of the patient. The CQI â??R-ICUâ?? evaluates quality of care from the perspective of relatives of intensive care patients and provides practical information for quality assurance and improvement programs. The development and psychometric evaluation of the CQI â??R-ICUâ?? led to a draft questionnaire, sufficient to justify further research into the reliability, validity, and the discriminative power of the questionnaire.