ABSTRACT: Hypertension is a major concomitant disease in hospitalized patients with COVID-19 (Coronavirus disease 2019) infection. The adverse effect of hypertension on prognosis in COVID-19 is known. Nevertheless, it is not known how COVID-19 progresses in resistant hypertensive patients. In this study, we aimed to examine the effect of resistant hypertension (ResHT) on in-hospital mortality in patients hospitalized with COVID-19. In our single-center retrospective study, included 1897 COVID-19 patients. The patients were divided into three groups according to the non-hypertensive (n = 1211), regulated HT (RegHT) (n = 574), and ResHT (n = 112). These three groups were compared according to demographic features, clinical signs, laboratory findings, and follow-up times. The median age of the study population was 62 (50-72 IQR) and 1000 (52.7%) of patients were male. The total mortality of the study population was 18.7% (n = 356). Mortality rates were similar in the hypertensive patient group (27.5% for the RegHT and 32.1% for ResHT, p = 0.321). In a multivariable analysis, ResHT was independently associated with a significantly increased risk of in-hospital mortality of COVID-19, while no significant increased risk was observed with RegHT [respectively, Odds Ratio (OR) = 2.013, Confidence Interval (CI) 1.085-3.734, p = 0.026 and OR = 1.194, CI 0.795-1.794, p = 0.394]. Also, age, male gender, chronic renal failure, lymphocyte, procalcitonin, creatinine, and admission SpO2 levels were determined as independent predictors of in-hospital mortality. In our study, it was found that ResHT was an independent predictor of mortality in patients hospitalized with COVID-19; however, this situation was not found in RegHT.