Necrotising fasciitis (NF) is mostly a polymicrobial, severe soft tissue infection that progresses rapidly, penetrating through the subcutaneous tissue to the fascial planes and the muscles. The pyoderma gangrenosum (PG), on the other hand, is a rare, rapidly progressive (except for the post‐surgical PG), autoinflammatory ulcerative skin and soft tissue condition. In this study, we tried to emphasise the importance of diagnosing the NF as well as the PG. Although these two clinical presentations have some standard features, awareness of different symptoms in detail affect the outcome. Any surgical discipline can face NF or PG and, therefore, should be aware of them to decrease the mortality rate. Forty‐five patients with NF and PG who were treated between January 2008 and October 2018 were included in the study and evaluated retrospectively for age, sex, localisation, onset of symptoms and diagnosis, predisposing factors, characteristics of tissue defects, laboratory findings, Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) scores, isolated microbiological agents, surgical intervention, and mortality rate. Demographic, laboratory, and clinical data were analysed. Among these 45 patients, 14 patients had PG, and 31 patients had NF. The mean age and SD for the NF and PG groups were 50.80 ± 17.67 and 50.78 ± 12.72, respectively. Five patients had rheumatological disorders; four patients had diabetes mellitus (DM) in the PG group. Males had higher risk than females in NF (odds ratio [OR] = 0.077, 95% confidence interval [CI] 0.017‐0.34), and females had higher risk in PG (relative risk [RR] = 5). We compared the LRINEC score of NF patients with PG patients. The mean value of this score was 4.53 for PG patients, and 6.06 for NF patients. Fifteen patients (33.3%) had a radiological evaluation. MRI, CT, and USI were used as imaging modalities. Necrotising fasciitis and PG are two distinct entities that are in general difficult to distinguish. Therefore, differential diagnosis and rapid treatment are crucial for lowering the mortality rate.