Purpose The recent outbreak of COVID-19 rapidly spread worldwide. Comorbid diseases are determinants of the severity of COVID-19 infection and mortality. The aim of this study was to explore the potential association between chronic kidney disease (CKD) and the severity of COVID-19 infection. Methods The study included 609 consecutive adult patients (male: 54.52%, mean age: 59.23 ± 15.55 years) hospitalized with the diagnosis of COVID-19 in a tertiary level hospital. Data were collected from the electronic health records of the hospital. The patients were separated into two groups: Group I included COVID-19-positive patients with CKD stage 1–2, and Group II included COVID-19-positive with CKD stage 3–5. The relationships were examined between CKD stage, laboratory parameters and mortality. Results Significant differences were determined between the groups in respect of the inflammation parameters and the parameters used in prognosis. In Group II, statistically significantly higher rates were determined of comorbid diseases [hypertension (p < 0.001) and diabetes mellitus (p < 0.001), acute kidney injury (AKI), which was found to be associated with mortality (p < 0.001), and mortality (p < 0.001)]. In multivariate regression analysis, CKD stage 3–5, AKI, male gender, hypertension, DM and malignancy were found to be significant independent variables increasing mortality. Conclusion The prevelance of CKD stage 3–5 on admission is associated with a high risk of in-hospital mortality in patients with COVID-19. Close follow-up can be recommended for patients with a reduced glomerular filtration rate (GFR).