Objective: Idiopathic granulomatous mastitis (IGM) is a rare condition that mimics breast cancer. Current treatment strategies include both surgical and medical therapy. This study aimed to report and describe the clinical signs, radiological findings, management, clinical course, and outcomes after treatment of IGM, from a major tertiary care institute in southern Thailand.Material and Methods: The medical records of 83 patients with IGM treated at our institute between January 2001 and April 2022 were retrospectively studied. Patient characteristics, clinical presentations, radiological findings, microbiological workups, tissue pathologies, treatment modalities, outcomes and follow-up data were reviewed and analyzed. The success rate, recurrence rate, and time to heal were compared between the different treatment modalities. Results: Overall, 83 patients were diagnosed with IGM. Due to insufficient follow-up periods, data from only 50 patients were used for the analysis. Initially, 34,3,8, and 5 were treated surgically, with steroids, anti-tuberculosis (TB) drugs, or other treatments, respectively; 32 (64%) achieved disease resolution. The median time to heal was 472 days, while the median time to heal after surgery, steroid therapy, anti-TB therapy, and others was 614.5, 333, 208.5, and 406 days, respectively. Surgery resulted in the longest time to heal; however, the difference was not statistically significant (p-value=0.23). Eighteen (36%) patients experienced recurrence.Conclusion: There was no significant difference among the treatment modalities in terms of time to heal and recurrence. Surgery resulted in the longest healing time, the highest incidence of complications, and a recurrence rate of approximately 50%. Surgical treatment should be reserved for aggressive diseases.