Serratia marcescens is an infrequent cause of cellulitis with only 5 reported cases. Four of the 5 patients were immunocompromised. Additionally, the cellulitis usually occurred at a site contiguous with a wound. We report a case of S. marcescens cellulitis in a patient with end-stage renal disease on chronic hemodialysis. The initial presentation was a soft tissue infection that progressed to septic shock. Ultimately, the patient responded to antibiotics and surgical debridement of infected tissue. This case serves as a reminder to consider infections due to gram-negative bacilli as a cause of cellulitis in immunocompromised patients regardless of the presentation.