Introduction. Influenza is a highly contagious acute respiratory illness. Due to the high exposure of hospital personnel, widespread vaccination of these high-risk groups seems to be a necessity in healthcare centers. To determine vaccination coverage in the personnel of four tertiary referral collegiate hospitals in 2019, and to further investigate individual obstacles for Influenza vaccination. Methods. In this cross-sectional descriptive study, 637 personnel were selected randomly from distinctive hospitals in a list-wised. Ones vaccinated filled the side effects questionnaire and who not vaccinated filled the vaccination obstacles questionnaire. Results. The mean vaccination coverage was 29.4% and the coverage difference among centers was not statistically significant (p=0.192). The following items had the most impact on personnel decision: confidence about one’s immune system (p<0.05), the experience of side effects from previous vaccinations (p=0.011), attitude about vaccination in colleagues (p=0.021) and work experience (p<0.05). About 23% of vaccinated individuals reported side effects following vaccination and the most common side effect was mild cold symptoms with 12.3% prevalence. Conclusion. The results of the current study revealed that influenza vaccination coverage among HCWs is not satisfactory in Iran. Hospital authorities and infection control units should plan to remove the obstacles of influenza vaccination.