Comorbidities were suspected and now have been known to increase patients’ susceptibility to contracting COVID-19 and the severity of a person who has been infected by Sars-CoV-2. Hypertension, diabetes mellitus and heart disease are pre-existing chronic conditions which were considered to increase the risk of infection and severity of infection, because of their prevalence in COVID-19 patients in Indonesia. An observational analytic study using a case-control approach was conducted. Total sampling method was used as the sampling method in this study. One hundred and two (102) patients with the radiographic depiction of pneumonia in Prof. dr. I.G.N.G. Ngoerah General Hospital from March 2020 until December 2020 met the inclusion criteria of the study. Additional information collected includes age, gender, COVID-19 RT-PCR test, history of hypertension, diabetes mellitus and heart disease and all the data were analyzed using multiple linear regression. Of 102 subjects, 63 (61.8%) patients have been confirmed positive for COVID-19 by RT-PCR testing. Male and female COVID-19 patient proportion is similar (54.9% vs. 45.1%). It was found that the proportion of old middle-aged adults was the highest among all COVID-19 patients (44 patients, 43,1%). History of hypertension was found in one-third of all COVID-19 patients (69 patients, 32,75%), diabetes mellitus also in one-third of all COVID-19 patients (63 patients, 29,8%) and some with heart disease (36 patients, 17%). A positive correlation was found between patients with symptomatic COVID-19 patients and hypertension (p=0.017), diabetes mellitus (p=0.013) and heart disease (p=0.283). At the moment this study was conducted, a large proportion of radiographic pneumonia patients are caused by Sars-CoV-2 infection. This study also found a positive significant correlation between the history of hypertension, diabetes mellitus, and heart disease with symptomatic COVID-19. Age and gender have no role in determining susceptibility and severity of COVID-19. Further studies are needed to describe other chronic diseases as a comorbidity in COVID-19 infection concerning their magnitude in causing a difference in susceptibility and severity in COVID-19 patients.