Background: The private health sector has a significant role in the delivery of health services in India. However, given fast changing COVID-19 pandemic, it is critical to understand the role of the private health sector in delivery of services going forward. The supply of COVID-19 vaccines is firmly regulated by the Government of India and the private sector received unrestricted access to vaccine supply directly from manufacturers from June 2021 onwards. Materials and Methods: PATH carried out a rapid assessment of private health facilities in the state of Maharashtra to understand the challenges faced by private facilities in providing COVID-19 vaccination. Results: During the assessment it was found that 100% of the private health facilities have a robust cold chain system which is essential for safe storage of COVID-19 vaccines and delivery of immunization services. The in-charges of the health facilities reported difficulty in estimating requirement of COVID-19 vaccines doses, as 67% of the beneficiaries in Mumbai and Nashik were direct walk-ins. During the assessment 93.3% of the facilities were observed to have adequate availability of COVID-19 vaccines doses, based on the beneficiary registration data for the day. Ministry of Health, Government of India, recommends a trained 5-member vaccination team for providing services at each vaccination site. Conclusion: The key challenges faced by private health facilities during delivery of COVID-19 immunization were associated with differential vaccine pricing, time taken to receive supply of vaccines, difficulties in accurately estimating vaccine demand, multiple record keeping at the facility level and declining vaccine demand.