Objective: To determine the validity and reliability of the Instrument to Identify Spiritual Suffering in Family Members of Patients with Mechanical Ventilation (IISEPVM). Method: Descriptive, methodological, this instrument evaluates the spiritual suffering of primary caregivers of mechanically ventilated patients based on the latest update of NANDA 2018-2020. The instrument is a modification of the "Questionnaire to Identify Spiritual Suffering" designed by Villagomez-Razo, Jordan-Jinez and Garcia-Campos in 2004. It was carried out with the participation of 15 primary caregivers and measurements were made with internal validity and reliability. Results: The age of the participants was 19 to 93 years (range 74 years). 93% female sex, 93% professed Catholic religion, 46% secondary schooling, 73% married and 60% have a monthly income of 0 to 1000 Mexican pesos. Level of spiritual suffering was mild. A Cronbach alpha of 0. 93 internal consistencies and an average covariance of 0. 18 were obtained. Conclusion: The application of IISEPVM is applicable to the primary caregiver context with mechanical ventilation patients, showing a safe validity and reliability. Key Words: Spirituality; Spiritual;
