Abstract : This study aims to determine the relationship between vitamin D serum level with disease activity in Systemic Lupus Erythematosus (SLE) subjects in Makassar. This study used a cross sectional design and was conducted in Wahidin Sudirohusodo Hospital and Universitas Hasanuddin Hospital Makassar, Indonesia. This study involved 40 subjects who were collected within a period of April 2021 to June 2021. All SLE subjects who met the inclusion and exclusion criterias as well as willing to participate in the study were for 25-Hidroxyvitamin D2 serum level. Subsequently, 25-Hidroxyvitamin D2 level obtained was then correlated with SLE activity level using MEX SLEDAI score. The collected data were analyzed with Statistical Package for Social Science (SPSS) version 22. Statistical analysis was carried out by calculating descriptive statistics and frequency distribution and the statistical test Fisher Exact. Based on the analysis results, it was found out that there was a significant negative correlation between vitamin D level and MEX SLEDAI score (p<0.05). Based on the category of vitamin D level and disease activities, it was found that severe disease activity is the highest in the group of subjects with vitamin D deficiency of 63.2%, while subjects having mild disease activity was the highest in the subject group of vitamin D sufficiency of 57.1% in which statistically it showed a significant correlation (p<0.05). The study found that the lower the level of vitamin D, the higher the degree of disease activity based on the Mex Sledai score.