Background: Although the coronavirus disease 2019 (COVID-19) pandemic continues to rage worldwide, clinical and laboratory studies of this disease have been limited in many countries. We investigated the epidemiologic, clinical, and laboratory findings of COVID-19 infected patients to identify the effective indicators correlated with the disease. Methods: A retrospective study was conducted at King Abdullah Hospital in Bisha Province, Saudi Arabia, from March 20 to June 30, 2020. Patients of different age groups were confirmed as having COVID-19 infection using a real-time polymerase chain reaction. The demographic, clinical, and laboratory data of the patients were statistically analyzed. Results: Of the 137 patients, 88 were male and 49 were female, with a mean age of 49.3 years (SD,18.4). The patients were elderly (n=29), adults (n=103), and children (n=5). Of these, 54 (39.4%) had comorbidities, 24% were admitted to the intensive care unit (ICU), and 12 (8.8%) died. On admission, the main clinical manifestations were fever (82.5%), cough (63.5%), shortness of breath (24.8%), chest pain (19.7%), and fatigue (18.2%). In all patients, increased neutrophils and decreased lymphocytes were observed. Patients' lactate dehydrogenase (LDH) was elevated. C-reactive protein (CRP) was elevated in 46.7%, D-dimer in 41.6%, and the erythrocyte sedimentation rate (ESR) in 39.4% of patients. The elderly showed higher neutrophil (p=0.003) and lower lymphocyte (p=0.001) counts than adults and children. Glucose, creatine kinase-MB, LDH, bilirubin, D-dimer, and ESR were significantly higher in the elderly than in the adults. The COVID-19 death group had a higher leucocyte count (p = 0.043), and higher urea (p=0.025) and potassium (p=0.026) than the recovered group but had a lower hemoglobin concentration (p=0.018). A significant association was determined between COVID-19 death (x2(1)=17.751, p<0.001), and the presence of cardiovascular disease (x2(1)=17.049, p<0.001), hypertension (x2(1)=7.659, p=0.006), renal failure (x2(1)=4.172, p<0.04), old age (t(135) = 4.747, p <0.001), and ICU admission (x2(1) = 17.751 (1), p<0.001). Conclusions: The common symptoms found in this study could be useful for identifying potential COVID-19 patients. Investigating some of the laboratory and clinical parameters could help assess the disease progression, risk of mortality, and follow up patients who could progress to a fatal condition.