Background: Melasma is a common acquired hyperpigmentation disorder that predominantly affects the face. It frequently occurs in women with darker skin types and severely impacts quality of life. Objective: To characterize the clinicoepidemiological features and triggering or aggravating factors of melasma in Korean patients. Methods: This cross-sectional study was conducted at the dermatology clinics of five university hospitals in Korea. Between January 2011 and August 2012, 411 patients with melasma completed a questionnaire about the clinical and aggravating factors associated with their melasma. Results: The study population consisted of 400 women and 11 men aged 22∼73 years (mean age, 42.8±9.92 years). Triggering or aggravating factors were sun exposure (68.4%), pregnancy (27.0%), and emotional stress (24.8%). Interestingly, 61.1% of patients complained of sensitive/inflammatory features such as erythema, itching, and a stinging sensation. Dryness was the most common aggravating factor, followed by erythema/redness and itching/stinging. Concomitant pigmentary disorders included post-inflammatory hyperpigmentation in 15.1% of patients, followed by pigmented contact dermatitis, and acquired bilateral nevus of Ota-like macules. Conclusion: It is well known that sun exposure and hormonal changes are the most common triggers of melasma; however, sensitive/inflammatory features may aggravate melasma in East Asian patients. Therefore, these individual and racial differences should be considered in the prevention and treatment of melasma. (Korean J Dermatol 2016;54(7):532∼537)