ObjectiveS: Necrotizing fasciitis (NF) requires surgical intervention and has high morbidity and mortality. Furthermore, it can be confusing with some skin diseases such as cellulitis. We investigated the roles of clinical and laboratory parameters at the time of admission to the hospital in the differential diagnosis of NF and cellulitis patients. Methods: Patients with cellulitis and NF located between the nipple level and the knee between January 2018 and January 2021 were included in our retrospective study. The fever, history, complete blood count results, blood biochemistry, C-reactive protein and procalcitonin values of the patients at the time of admission to the emergency department, length of hospital stay, mortality rates, and laboratory risk indicator for necrotizing fasciitis (LRINEC) scores were recorded and evaluated whether there was a difference in both patient groups. Results: A total of 55 patients, including 26 patients in the NF group and 29 patients in the cellulite group, were included in the study. It was observed that patients with NF applied to the hospital statistically earlier, had higher leukocyte, platelet and neutrophil levels, had longer hospital stays and had higher mortality numbers. Conclusion: In high leukocyte, platelet, and neutrophil levels in the case of cellulitis patients, the clinician should follow the patient's clinic course closely and keep NF in mind. [ABSTRACT FROM AUTHOR]