Objective: To demonstrate the reliability and construct validity of Karasek's Job Content Questionnaire (JCQ), which measures psychological demands, job control and social support, in nursing personnel. Theoretical Framework: In Mexico, the Federal Labor Law specifies that psychosocial risks must be kept at low or zero levels to prevent work-related stress in nursing staff. Method: The Job Content Questionnaire was applied to a sample of 181 nursing professionals from a population of 200 people. The internal consistency of the questionnaire was examined using the Cronbach's Alpha reliability coefficient, the construct validity of the questionnaire was identified through the fit indices of the confirmatory factor analysis, using the maximum likelihood method. Results and Discussion: The results obtained revealed [synthesize the main results of the research]. In the discussion section, these results are contextualized in light of the theoretical framework, highlighting the implications and relationships identified. Possible discrepancies and limitations of the study are also considered in this section. Research Implications: The Job Content Questionnaire presented adequate internal consistency (Cronbach's Alpha=.80) and construct validity in the sample; the structural equation model presented an adequate fit: GFI=.73, RMSEA=.066, NNFI= .93, CFI=.94, PNFI=.78. These findings affirm that the Job Content Questionnaire is valid and reliable to evaluate psychosocial factors among workers who perform nursing activities in Mexico. Originality/Value: This study contributes to the literature by demonstrating the reliability and validity of the Job Content Questionnaire in nursing in Mexico. Its effectiveness is confirmed to evaluate psychological demands, work control and social support, critical aspects to mitigate stress and improve the quality of work life. The results can influence labor policies and institutional practices, promoting healthier work environments, reducing stress and improving the quality of care in the health sector, which benefits both workers and patients.