To explore the causes and treatment outcomes of intrauterine adhesions among Thai women. This retrospective cross-sectional study recorded and analyzed the demographic data, causes, and treatment outcomes of 75 patients who underwent hysteroscopic adhesiolysis between January 2004 and June 2015 at Maharaj Nakhon Chiang Mai Hospital, Chiang Mai, Thailand. The most common etiology of intrauterine adhesions was a history of early pregnancy termination by curettage (68%). Sixty-nine percent of the patients had menstrual abnormalities. Twenty-two percent of the patients had severe adhesions. Tuberculous endometritis caused the most severe case. Sharp hysteroscopic adhesiolysis improved the condition in 77.7% of the patients. The outcomes of the patients with mild to moderate IUA were better than those with severe intrauterine adhesions (88.2% vs. 43.8%, respectively) (p = 0.001). Fifty-one patients planned to conceive, and 49% succeeded after hysteroscopic surgery. Menstrual abnormalities were the most common presentation of intrauterine adhesions. The most common cause of intrauterine adhesions was early pregnancy termination by curettage. However, tuberculosis endometritis caused the most severe case. Hysteroscopic adhesiolysis significantly improves menstrual function and fertility outcomes; mild to moderate cases have a better prognosis.