Abstract : SARS-COV2 causes highly contagious, brand-new emerging disease called Covid-19. Unlike other zoonotic disease, the disease transmit human to human. As massive mobility spread throughout the world, we should find a method to detect and stop the transmission. Hospital-based surveillance was one of surveillance strategy that was effective to early detection and easy to apply. This study described application of hospital-based surveillance strategy in one of national referral hospital for infectious disease. We analyse trends in People Under Observation (PUO), Patients Under Investigation (PUI), and mortality rate in beginning of pandemic era in Indonesia. These findings have become part of the National guideline for Covid-19 prevention and control in the surveillance and clinical management chapter. We studied PUO in early pandemic era in Indonesia from February 1st to May 31st 2020. We also analyse inpatient cases (PUI) of COVID-19 in Sulianti Saroso Infectious Disease Hospital throughout the year. We analysed hospital-based surveillance system, by the case terminology proposed in the National Guideline. Case confirmed was signed by positive RT-PCR via nasopharynx and oropharynx swab. Data analysis was done by performing frequency measurement and chi-square. We screened a total of 2555 PUO during the study in the beginning of pandemic in Indonesia with travel history to region where covid-19 had already presented, history of close contact and/or presented covid-19 like symptoms. Until the end of 2022, we treated 3928 Patients Under Investigation which 3694 of them (82.6%) were confirmed COVID-19 cases. Most of the confirmed case was male (50.4%) in 19-59 years old (66,7%). The most presented symptoms were cough (78,5%), fever (51,5%), and shortness of breath (37%). Among the confirmed cases, 1076 cases were treated in intensive room (29,12%). We remarkably found majority cases weren’t presented comorbid disease (86,6%). Mortality rate reached to 13% while length of stay more than 14 days seized 23,8%. We performed hospital-based surveillance as a quick response to brand new emerging disease, covid-19. A quick and simple screening was needed for rapid case detection and prevent advance transmission. Hospital-based surveillance was also required to project health care capacity.