During intensive care unit (ICU) management of COVID-19, blood tests are often conducted for close monitoring of patients, a poor prognostic factor for survival, especially in hypoxemic patients. This study aimed to determine the degree of anemia and its effect on prognosis in ICU COVID-19 patients. This retrospective study included COVID-19 patients admitted to the ICU between 1 October 2020 and 1 May 2021. All the patients included were aged > 18 years and stayed in the ICU for ≥14 days. Patients aged <18 years, those with major bleeding, and those recovering from surgery were excluded. The total blood samples (mL) taken in the ICU were calculated. From among the 395 patients screened for inclusion, 112 patients were included in the study. Mean age of the patients was 71.3 ± 13.2 years (Male/Female: 1.8). Mean hemoglobin (Hb) at admission was 13.2 ± 1.8 g dL–1. At the end of the ICU stay mean Hb was 9.74 ± 1.98 g dL–1. During ICU stay, the mean reduction in Hb was 3.47 ± 2.11 g dL–1. Age (p= 0.049), drawn blood volume per day (p= 0.001), and higher hemoglobin at admission (p= 0.001) were determined by multivariate analysis as independent risk factors for hemoglobin reduction. Hemoglobin reduction (OR: 1.34), and intubation status (OR: 57.50) were independent risk factors for mortality. Considering that most COVID-19 patients are admitted to the ICU due to acute respiratory failure (ARF), it is vital to maintain the Hb level as high as possible, so as to maintain oxygenation.