Background and Aims: In 2019, a novel coronavirus called SARS-COV-2 spread throughout the world, causing a pandemic a few months later. As the virus is not well-known and highly contagious, it is important to observe patients for all possible symptoms and comorbidities. This study aimed to demonstrate some demographic, clinical, and paraclinical features of the deceased patients with COVID-19 in Iran. Materials and Methods: A retrospective observational study was designed to demonstrate the clinical and paraclinical features of deceased patients who had a positive real time-polymerase chain reaction test result for COVID-19. The study included all COVID-19 patients who visited Shariati Hospital, Tehran, Iran, from February 20th until May 20th, 2020. All data were analyzed using IBM SPSS version 21 (Mann-Whitney or Fisher’s test). Results: The patients had a mean age of 63.86 ± 16.428, and most were males (59.65%). Diabetes and hypertension were the most frequent comorbidities. The most common symptoms among the patients were dyspnea (64.91%), weakness (61.40%), fever (60.71%), and having ground-glass opacities in the CT scans (85.96%). There was also a rise in lactate dehydrogenase, serum ferritin, D-dimer, and procalcitonin. Conclusions: Older COVID-19 patients are more likely to get more severe forms of the disease. Most of the deceased COVID-19 patients had ground-glass opacities in their CT scans. Dyspnea, fatigue, and fever were the most frequent symptoms. Hypertension and diabetes were the most important comorbidities. There was almost no significant difference between the two genders regarding clinical and paraclinical symptoms.