Background:Several studies reported the association between olfactory dysfunction and the novel coronavirus disease in 2019 (COVID-19). Objective: This study aimed to investigate the effect of vitamin D and omega-3 long-chain polyunsaturated fatty acids on anosmia and COVID-19-induced proinflammatory cytokines. Subjects and methods: This is a supervised randomized prospective experiment performed at the Hospital of Faculty of Medicine, Benha University. It was performed on two groups; 110 cases per group were used; one was considered healthy control and the other showed anosmia after COVID-19 infection. Evaluation of the vitamin D and omega-3 impacts on decreasing anosmia and COVID-19-induced cytokines was performed using Sniffin' Sticks test and cytokines' serum tests, respectively. Results: A number of 110 patients from each group had persistent anosmia; the smell scores with the Sniffin' Sticks test on the initial assessment were low. The levels of IFNγ, TNFα, IL4, IL6, and IL10 cytokines and CRP were higher in both groups than in the healthy control group  (p < /em> < 0.05). On the 10^th, 20^th, and 30^th days, there were improvements in the smell scores and decrease in the IFNγ, TNFα, IL4, IL6, and IL10 cytokines and CRP in the treatment group than in the control group (p < /em> < 0.05). The duration of recovering the sense of smell was shorter in the treatment group than in the control group (24.1 ± 1.35 days vs. 28.9 ± 0.93, p < /em> < 0.05). Conclusion: Vitamin D and omega-3 long-chain polyunsaturated fatty acids may decrease the exaggerated cytokines and improve olfaction after COVID-19 infection.