Background COVID-19 has rapidly spread across the world at an unprecedented rate. The outbreak of COVID-19 infection has led to a significant health burden on infected patients, especially those with existing comorbidities. The aim of this study is to find the most prevalent symptoms, comorbidities, and complications developed during the course of the disease and outline the most prevalent symptoms among the baseline and clinical characteristics of the patients. Methods This is a retrospective study that was performed on the data obtained from medical records of 3999 COVID-19 patients from Prince Mohammed Bin Abdulaziz Hospital in Riyadh, Saudi Arabia. Demographic data, clinical symptoms, and comorbidities were noted on the day of hospital admission. Complications developed during the COVID -19 infection were also observed. Results The average age was 49.55 ± 14.75 years and 73.77% of the study population were male patients. The average Body Mass Index (BMI) of the patients was 29.48 ± 6.94. Fever and cough were the most common symptoms (85.85%) followed by shortness of breath (83.25%). Other reported symptoms were diarrhoea (17.43%), fatigue (16.2%), vomiting (15.38%), headache (15.23%), sore throat (9.3%), and nausea (8.5%) The most common comorbidity recorded was diabetes mellitus (DM) (39.51%), followed by hypertension (HTN) (33.91%), and asthma (9.45%). In COVID-19 patients with comorbidities, 61.90% developed complications of pneumonia, 8.73% had Acute Respiratory Distress Syndrome (ARDS), 7.25% developed pneumonia and ARDS concurrently, while 0.4% of the total patients had septic shock. Conclusion The symptoms of fever, cough, and shortness of breath were higher in individuals with hypertension and diabetes mellitus, and more prevalent in complications of pneumonia, acute respiratory illness, and septic shock.