Although rare in immunocompetent patients, infection caused by Serratia marcescens is difficult to treat due to its antimicrobial multiresistance. A 33-year-old male visited our hospital because of recurrent multiple erythematous tender nodules and sinus tract on the nape. The gram negative bacteria were cultured through the pus swab and revealed to be sensitive to ciprofloxacin. After treating with the susceptible antibiotic, the lesions showed gradual resolution. It is necessary to find an accurate pathogen and the susceptible antibiotics in the intractable hidradenitis suppurativa in a healthy patient. Here, we present a case in which the immunocompetent patient infected with Serratia marcescens at the site of hidradenitis suppurativa lesion.