||Objective. To analyze operating room nurses experienced stress factors, occurrence of fatigue and relations between fatigue and stress at work. Methods. The research took place in Vilnius University hospitals from April to August in 2015. A qualitative research method – questionnaire was used. One hundred ninety three operating room nurses from 7 Vilnius city health care institutions took part. Stress factors experienced by operating room nurses, occurrence of fatigue and the interfaces between fatigue and stress at work were evaluated during this research. “The Multidimensional Fatigue Inventory” MFI-20 (A. Stankus) was used to evaluate chronic fatigue of nurses . Evaluation of general, physical and mental exhaustions, reduced activity and motivation were performed using this instrument. Questionnaire ”Stress at work rating by psychosocial work factors and stressful employee reactions“ written by B. Pajarskienė and R. Jankauskas was used to evaluate experienced stress at work by nurses. Six factors: 1. possibilities of the impact, 2. work requirements, 3. rush and work arrangement, 4. stress at work, 5. evaluation, 6. responsibility were evaluated. Permission by Bioethics Center of Lithuanian Health Sciences University No. BEC-KS (M)-421 was received for the research. Descriptive statistics was used for statistic quantitative data; frequencies and average values were analyzed; nonparametric data analysis tests were applied. Results. The research showed the occurrence of fatigue among operating room nurses. Total experienced exhaustion average was 39.48%. One third of operating room nurses experienced physical (average 33.81%) and mental (average 29.53%) exhaustion, decreased motivation (average 29.60%), and reduced activity (26.55%). Evaluation of the occurrence of fatigue by nurses sociodemographic characteristics was found to be statistically significant (p<0.05); general fatigue was more experienced by unmarried (single) nurse; their motivation was the most reduced. Mental fatigue was experienced more by widowed or unmarried (single) nurses (p<0.05). Experienced fatigue depended on the length of service: nurses with 11-15 years of work experience had bigger physical fatigue and reduced activity (p<0.05). There was also a statistically significant difference between fatigue and nurses education: general, physical and mental fatigues were experienced more by nurses with higher education compared to nurses with high degree education (p<0.05). The evaluation of the relation between expierienced fatigue and nurses age revealed that activity with increasing age was getting lower (p<0.01). The evaluation of the operating nurses stress factors showed that the greatest stress was caused by possibilities of the impact (average 12.69%), rush and work arrangement (average of 12.21%), responsibility (11%). Conclusions. Results for chronic exhaustion relation to stress among operating room assistants allowed identifying the main factors causing this. The experienced stress and exhaustion depends on the sociodemographic characteristics: marital status, working experience, education and age.