Aims: To determine nurses' job stress and its relationship with professional autonomy and nurse-physician collaboration in intensive care unit (ICU).

Background: Low professional autonomy, high job stress and lack of nurse-physician collaboration can affect nursing care in ICU and the main reasons ICU nurses leave the occupation or transfer to other clinical units.

Methods: A cross-sectional, correlational study was conducted on 398 nurses in teaching hospitals in Urmia, Iran, in 2020. Data were collected using the Dempster Practice Behaviors Scale, the Health and Safety Executive tool and the Jefferson Scale of Attitudes toward Physician-Nurse Collaboration.

Results: The mean job stress (115.53 ± 12.42) and professional autonomy (102.19 ± 11.88) of ICU nurses were 'moderate', and nurse-physician collaboration (74.25 ± 5.10) was 'good'. There was a positive relationship between professional autonomy and job stress (r = .506) and nurse-physician collaboration (r = .242). Professional autonomy was a predictor of job stress in nurses (p < .000), and work experience in ICU can cause job stress in nurses (p = .024).

Conclusion: Increasing nurses' professional autonomy causes an increase in job stress and improves nurse-physician collaboration in ICU.

Implications for nursing management: Nursing managers should implement practical strategies to improve nurses' autonomy, enhance nurse-physician collaboration and decrease their job stress.