BACKGROUND: Mycobacterium mucogenicum is a rare but emerging cause of infections, especially in immunocompromised patients. METHODS: We describe a new case of M. mucogenicum catheter-related bloodstream infection in a 34-year-old woman with ovarian cancer. M. mucogenicum was at first considered as a contaminant, and susceptibility testing was not performed. Usual susceptibility of M. mucogenicum motivated prescription of clarithromycin and moxifloxacin. Finally, our isolate was confirmed susceptible to both drugs. Clinical outcome was favorable with no relapse of infection after antibiotics discontinuation despite concomitant chemotherapy. CONCLUSIONS: Our case illustrates the need for a clinician-microbiologist dialogue in case of suspected M. mucogenicum infection to avoid delaying appropriate management.