<![CDATA[Oil spills into marine waters, directly and indirectly, cause pollution that impacts biodiversity and the social economy of the community. This study evaluated and determined the economic valuation of ecosystems affected by oil spills in Balikpapan City. The research method uses revealed preferences from previous similar cases and is based on survey results. The survey results showed that the affected ecosystems were spread over 12 urban villages in Balikpapan City, with ecosystem types including mangrove ecosystems, seagrass beds, coasts, and marine waters. In addition, it also results in socio- economic losses for the community, especially for fishers in the city of Balikpapan. The PT PERTAMINA RU V oil spill in Balikpapan Bay impacts biota deaths due to poisoning of marine biota ecosystems, causing economic losses to the community. Marine biota such as fish, shrimp, and shellfish are reduced, damaging marine biota ecosystems such as spawning and damage to habitat and function. The impact of the affected ecosystem also resulted in considerable losses in efforts to recover from the damage caused by the oil spill. Keywords: Balikpapan_city, economic_valuation, marine_ecosystem, oil_spill ABSTRAK Tumpahan minyak ke perairan laut secara langsung dan tidak langsung menyebabkan pencemaran yang berdampak pada keragaman hayati dan ekonomi sosial masyarakat. Penelitian ini bertujuan untuk mengevaluasi dan menentukan valuasi ekonomi ekosistem terdampak tumpahan minyak Teluk Balikpapan di Kota Balikpapan. Metode penelitian menggunakan revealed preference dari kasus sebelumnya yang serupa dan berdasarkan hasil survey. Hasil survey didapatkan jenis ekosistem yang terdampak yaitu tersebar di 12 kelurahan di Kota Balikpapan, dengan jenis ekosistem diantaranya ekosistem mangrove, padang lamun, pesisir, dan perairan laut. Selain itu juga mengakibatkan kerugian sosial ekonomi masyarakat, khususnya bagi nelayan di Kota Balikpapan. Tumpahan minyak PT PERTAMINA RU V di Teluk Balikpapan berdampak terhadap kematian akibat keracunan ekosistem biota laut, sehingga menyebabkan kerugian ekonomi masyarakat. Biota laut seperti ikan, udang, kerang berkurang, kerusakan ekosistem biota laut seperti pemijahan dan kerusakan habitat dan fungsi. Dampak ekosisstem terdampak juga mengakibatkan kerugian yang besar dalam upaya pemulihan akibat kerusakan oleh tumpahan minyak. Kata kunci: Ekosistem_Laut, Kota_Balikpapan, Tumpahan_minyak, valuasi_ekonomi]]>
