The prevalence of nontuberculous mycobacterial (NTM) infections are rising and Mycobacterium abscesses is a fast-growing NTM that is frequently linked to infections of skin and soft tissues. We report the case of a 31-year-old immunocompetent woman who presented with a history of a painful right breast lump with discharge following five days of antibiotic therapy in a community health facility with no discernible improvement. The patient underwent quadrantectomy at our hospital after being diagnosed with breast abscess. Histopathological examination revealed Granulomatous Mastitis with abscess formation of right breast. Ziehl-Neelsen stain was positive for Acid Fast Bacilli, Gram staining of representative tissue and pus revealed pus cells with free of microorganisms and GeneXpert MTb/Rif assay revealed no MTb, indicating Mycobacterium other than tuberculosis infection. Non-tuberculous Mycobacteria were detected in the acid-fast bacilli (AFB) culture and MALDI-TOF further identified the isolate as Mycobacterium abscesses. Antimicrobial susceptibility test by broth microdilution assay revealed susceptibility to clarithromycin, amikacin, ciprofloxacin, linezolid and intermediate susceptibility to cefoxitin. The patient was prescribed clarithromycin, linezolid, amikacin resulted in a stable and uneventful discharge.