Background: Volcano eruptions may result in a wide range of health impacts. Exposure to volcanic materials may irritate respiratory tract, eyes, and skin, in addition to death and heat injury. Mount Merapi had two consecutive eruptions on 2010 and resulted in high number of mortality and morbidity. This study aimed at assessing prominent diseases among internally displaced persons after Merapi eruption in Indonesia.

Methods: It is a cross sectional study, attached on delivery of medical aids by Faculty of Medicine Universitas Indonesia, on the fi rst and second week after the second Merapi eruption, in twelve evacuation posts within Muntilan and Mertayudan sub-districts. Analysis of prominent diseases was carried out after grouping the working diagnoses according to the International Classifi cation of Diseases-10.

Results: With a range of 1 to 4 diagnoses per person, total numbers of diseases or disorders for analysis were 804 diseases or disorders. Four top diseases on Week 1 after the second Merapi eruption were (1) respiratory track diseases, (2) other soft issue disorders, not elsewhere classifi ed, (3) hypertension, and (4) episodic and paroxysmal disorders. On Week 2, respiratory track diseases, hypertension, and skin and subcutaneous tissue diseases had increasing proportion.

Conclusion: Respiratory tract diseases, hypertension, skin and subcutaneous tissue diseases increased on week 2 after the second Merapi eruption compared to week 1. (Health Science Indones 2013;2:-)