Necrotizing fasciitis is a severe soft tissue infection characterized by rapidly progressing necrosis, involving subcutaneous tissues. This rare condition carries high mortality rate and require prompt diagnosis and urgent treatment with radical debridement and antibiotics. We describe a case of 21-year old man who presented with the history of trivial injury to the knee. Initially he was admitted and treated for septic arthritis but later was diagnosed as necrotizing fasciitis which was successfully treated with no ill effects what so ever from this devastating condition. This rare condition has been reported in literature but still early diagnosis, which is a key for successful treatment, remains a challenge.