Objectives: The Patient Evaluation of Emotional Comfort Experienced (PEECE) is a 12-item questionnaire which measures the mental well-being state of emotional comfort in patients. The instrument was developed using previous qualitative work and published literature. Design: Instrument development. Setting: Acute Care Public Hospital, Western Australia. Participants: Sample of 374 patients. Interventions: A multidisciplinary expert panel assessed the face and content validity of the instrument and following a pilot study, the psychometric properties of the instrument were explored. Main outcome measures: Exploratory and confirmatory factor analysis assessed the underlying dimensions of the PEECE instrument; Cronbach's α was used to determine the reliability; ? was used for test-retest reliability of the ordinal items. Results: 2 factors were identified in the instrument and named 'positive emotions' and 'perceived meaning'. A greater proportion of male patients were found to report positive emotions compared with female patients. The instrument was found to be feasible, reliable and valid for use with inpatients and outpatients. Conclusions: PEECE was found to be a feasible instrument for use with inpatient and outpatients, being easily understood and completed. Further psychometric testing is recommended.