Background: The aim of the study was to assess the effect of the training program on knowledge, attitude and practice (KAP) related to prevention and management of COVID-19.Methods: A pre-post study was conducted among healthcare workers (HCWs) attending ten-days online training program from 29 April to 30 November, 2020. A 37-item questionnaire assessing knowledge (26-items), attitude (6-items) and practice (5-itmes) was administered to the participants before and after the training program. Total score of knowledge, attitude and practice (KAP) was 27, 12 and 20 respectively. Paired t test was used to assess the effect of training on KAP. Association of pre-training KAP with demographic variables was performed using SPSSv-22.Results: A total of 1428 HCWs were trained across 25 states through nine trainings; however, the data was analysed for only 1167 HCWs (response rate: 82%). Mean age of participants was 30.96±6.62 years and 77.29% were females. Mean KAP scores in pre-training were found to be 17.46±3.24 out of 27, 9.94±1.56 out of 12 and 19.01±1.76 out of 20 respectively which significantly increased to 21.28±3.65, 10.35±1.48 and 19.37±1.49 after attending training program. Pre-knowledge score was found to be associated with age, years of experience, geographical location, type of facility, presence of COVID-19 related facilities in the place of working.Conclusions: Comprehensively designed training program enhanced the knowledge about prevention and management of COVID-19 in HCWs and also motivated them to maintain an optimistic attitude and good practices while managing the patients.