Peritoneal tuberculosis (TB) is a rare extrapulmonary manifestation of TB with non-specific clinical characteristics which can produce test results mimicking malignancy and granulomatous peritonitis. This case describes a Filipino 59-year-old, nulliparous woman who was admitted with abdominal pain, ascites, and an elevated CA-125 level. Radiographically, peritoneal nodules were visualized and initial suspicion was high for malignancy. Following a bilateral salpingo-oophorectomy and peritoneal biopsy, histology was negative for malignancy but revealed non-caseating granulomas. She was discharged then readmitted with progressive abdominal pain, and a repeat laparoscopic biopsy yielded specimens with growth of acid-fast bacilli (AFB). A delay in diagnosis and treatment of tuberculous peritonitis increases mortality rates, making early diagnosis with laparoscopic biopsy of paramount importance in prompt diagnosis and initiation of therapy. This patient was initiated on standard anti-TB therapy and experienced no complications.