Objectives The present study aimed to evaluate the presence of any relationship between vitamin D and prognostic factors among patients infected with SARS-CoV-2. Methods This retrospective cross-sectional study was conducted among patients admitted from March to August 2020 in a referral hospital, Tehran, Iran. All patients aged 18–65 who had not any comorbidity participated in the study. The diagnosis of COVID-19 was established using the rRT-PCR test for SARS-CoV-2 detection. Then the incidence of lung involvement and biochemical markers including vitamin D level, c-reactive protein, D-dimer, lymphocyte count, platelet count, white blood cell count, and lactic acid dehydrogenase, were extracted through medical records. Results Altogether, 84 patients met our study criteria, and the information of 68 (80.9%) participants were collected. Among all 68 patients, 45 (66.2%) were male. The mean (SD) age of all participants was 52.4 (10.4) years old. Among 24 (35.2%) clients who died due to SARS-CoV-2, 20 (83.3%) patients were male (p=0.02). The mean (SD) of vitamin D level was 24.1 (13.6) ng/dL. No association between vitamin D level and prognostic factors, including CRP, lymphocyte count, D-dimer, LDH, and HRCT scan score, was observed. Also, the vitamin D level of the dead patients was not significantly different from that of the treated patients. Conclusions Our findings indicated no significant relationship between vitamin D level and prognostic factors or outcomes of patients infected with SARS-CoV-2.