Objective. To investigate the course of biomarkers on admission and follow-up in order to identify early predictors for poor outcome in COVID-19 patients. Methods. In this study, 132 COVID-19 patients were classified as good outcome (n=62) and poor outcome (n=70) groups. Laboratory parameters were evaluated on admission and within 5-7 days after hospitalization. Results. Baseline levels of neutrophil-lymphocyte ratio, CRP, procalcitonin, ferritin, D-dimer and LDH were higher (p<0.01); lymphocyte count was lower in the poor outcome patients. During follow-up there was a larger decrease in lymphocyte count and more prominent increases in other biomarkers (p<0.001). In ROC analysis, the AUCs strongly indicated the poor outcome on days 5-7 of the hospitalization. Conclusions. This study suggests that the follow-up measurements of the biomarkers better predict the poor outcome in COVID-19 pneumonia.