Background: After the first patient of COVID-19 was announced by the Ministry of Health in Tanzania from Arusha region, the hottest discussion in the community was the fear on how our health facilities were prepared against the spread of coronavirus disease. Objective and significance: This study aims at assessing healthcare facilities level of preparedness response on preventive measures against COVID-19 in selected regions of Tanzania through the contributions of healthcare workers. This study will add value in building capacity to fight COVID-19 pandemic and possibly any other pandemic of similar significance in the future. Methods: Analytical cross-sectional study design which applied quantitative research strategy was conducted from August to October 2022. A total of 596 healthcare workers were involved in the study from 40 healthcare facilities in Dar es Salaam, Mwanza, Arusha, and Dodoma regions of Tanzania. Descriptive statistics were analyzed by a statistical package SPSS version 26 (IBM Corp., Armonk, NY) giving frequencies, percentages, and significant association between variables. Results: Overall level of preparedness was poor at 52%, only 25% of preventive measures were good prepared and 23% moderately prepared. Availability of hand washing station with soap and water to ensure hand hygiene for healthcare workers was most prepared by 87.1% while designated ambulance facility for transporting patients from isolation area to other COVID-19 referral facilities was less prepared by 30.4% in this study. Conclusion: The preparedness responses was poor in selected regions of Tanzania which cause less capacity to fight against COVID-19 whenever it emerges.