Abstract. Setiawan W, Harianto SP, Rommy Qurniati R. 2017. Ecotourism development to preserve mangrove conservation effort: Case study in Margasari Village, District of East Lampung,. The conservation efforts by Margasari community have produced the enhancement of mangrove forest areas, however the utilization of mangrove forest by people around was low. To make the conservation effort sustainable needs to develop mangrove ecotourism so they can utilize mangrove forest existence. This research intended to study the conservation and ecotourism effort in Margasari Village and the community perception of ecotourism development. This research was conducted in March-April 2017 in Margasari Village by interviewing 96 respondents. The data collection was undertaken through field observation, key informant interviews, and structured interviews with questionnaire. The result showed, the conservation effort was protecting, preserving, and utilizing of mangrove such as mangrove nursery, mangrove plantation, utilizing of jeruju and pedada fruit as food and counselling to the villagers not to cut mangrove and enter the mangrove forest. The ecotourism activities were boating around the mangrove, mangrove planting tourism, and bird watching. The conservation and ecotourism effort conduct by the people who joined community groups. But it was dominated by the group manager. So the financial benefit from ecotourism had limited for few people. Nevertheless, Margasari community agreed with the ecotourism development and was willing to participate in developing the ecotourism.