Hormonal changes in pregnancy are the important etiology of melasma. The presence of melasma in more than 75% of pregnancies. At the end of pregnancy, estrogen levels increase. Estrogen, especially estradiol triggers increased synthesis of melanin. This paper is aimed to determine the relationship between estradiol hormone with melasma and the type ofmelasma in pregnant women. This study used a cross-sectional study design to determine the relationship of estradiol hormone with melasma. It was conducted from September-November 2015. Skin examination was performed on 64 pregnant women (15-49 years old) who suffered from melasma in the third trimester and who did not, and the blood was drawn to measure the level of serum estradiol hormone. The study results that the levels of estradiol was slightly higher in women with melasma than those without melasma (13811.7 vs 12820.5), but not statistically significant (p>0.05). There was slightly higher levels of estradiol in women with the mixed type of melasma than the other types (14444.10 vs 14047.25 and 12243.50), but it was not statistically significant (p>0.05). Estradiol levels correlated significantly (p<0.05) with maternal age (r = 0.238) and gestational age (r = 0.435); but did not correlate significantly (p>0.05) with MASI (Melasma Area Severity Index) score and the type of melasma. The study concluded that estradiol levels in women with melasma are higher than not melasma and in mothers with type mix melasma were higher than other types, but not statistically significant. Estradiol level correlated with maternal age and gestational age.