Aim: Our study was designed on the hypothesis that homocysteine levels are a prognostic parameter that can predict the severity of COVID-19 disease. Materials & methods: 117 COVID-19 patients and 34 non COVID-19 individuals were included in the study. Receiver operating characteristic (ROC) analysis was performed for homocysteine, D-dimer and monocyte/lymphocyte ratio (MLR) levels. Results: According to the ROC analysis, in COVID-19 patients group, Area under curve (AUC) values were 0.835 for homocysteine, 0.859 for D-dimer and 0.882 for MLR. According to the ROC analysis, in which homocysteine, MLR and D-dimer parameters were evaluated together, AUC values were 0.951 in the mild disease group, 1000 in severe disease group and 0.967 in COVID-19 patients group. Conclusion: It was concluded that homocysteine level is an important parameter in the follow-up of COVID-19 disease.