Abstract : Myasthenia gravis (MG) is a rare autoimmune disorder caused by antibodies that destroy receptors in the post-synaptic neuromuscular junction. The production of antibodies is related to the failure of the T-regulatory cell to destroy the autoreactive cell. This research aims to analyze the differences in Treg levels between selected MG patients and healthy controls. Myasthenia gravis patients were patients in RSUP Dr. Kariadi Hospital Semarang that met inclusion and exclusion criteria. The healthy controls were gender-matched with the MG patient group and got physical examination and questionnaire to establish as ‘healthy’. Treg analysis with flowcytometry and BD bioscience Treg cocktail that identify as CD4+CD25brightCD127dim. Analysis variable with SPSS 28.00 There is no significant correlation between Treg level and other variables, like age, disease duration, severity, or the level of the antibody acetylcholine receptor. The mean Treg level in the MG group compared to the healthy group is 4,75% vs 12,81%. There is a significant difference in the level of Treg serum in patient MG compared with healthy controls (p≤0,001). There is no significant difference between CD4+ and CD25+ between the two groups.