Serratia plymuthica is gram negative short bacillus which is an uncommon cause of human infection. Previously, it was considered as nonpathogenic bacteria, but it turned out to be a pathogen causing bacteremia, sepsis, osteomyelitis and surgical wound infection. A 73-year-old female visited the clinic with purpuric nodule on her right hand. It first appeared 3 months ago and there was no change in size or shape. The skin lesion was asymptomatic and there was no history of trauma. Histopathological examination showed granulomatous inflammation with giant cells and epidermal hyperplasia. Serratia plymuthica was isolated from tissue culture. She was treated with ethambutol, clarithromycin and doxycycline for 7 weeks. The lesion was completely cured and has not recurred since 9 months after treatment. According to previous reports, Serratia plymuthica can cause nosocomial infection such as burn scar infections and surgical wound infections. However, our patient had no history of any interventions on her right hand. Here we report a case of Serratia plymuthica infection in social community.