Abstrak: Ikan hasil produksi Waduk Jatiluhur dicurigai mengandung senyawa kimia berbahaya karena air waduk diduga kuat sudah tercemar limbah industri dan pakan ikan sendiri, selain akibat pencemaran dari Sungai Citarum dan Sungai Cilalawi. Penelitian ini dilakukan untuk mengetahui kontaminasi logam berat merkuri pada air, ikan budidaya air tawar keramba jaring apung, dan ikan liar di Waduk Jatiluhur. Jenis sampel ikan dipilih berdasarkan ikan yang banyak dibudidayakan di Waduk Jatiluhur, yaitu Ikan Nila, Mas, dan Red Devil. Dari pemeriksaan yang dilakukan diketahui nilai rata-rata kandungan Hg dalam ikan Red Ikan Nila, Mas, dan Red Devil berturut-turut adalah 1,38.10-6; 1,74.10-6; 3,61.10-6 mg/kg. Dari ketiga jenis ikan yang dijadikan penelitian urutan konsentrasi Hg dalam ikan diurutkan dari yang terbesar, yaitu Red Devil > Mas > Nila. Konsentrasi Hg terbesar berdasarkan organ yang diteliti adalah insang > daging > kulit. Konsentrasi Hg dalam ikan tergolong sangat kecil jauh dari batas nilai 0,5 mg/kg yang ditetapkan oleh Peraturan Kepala Badan POM no. HK.00.06.1.524011. Walaupun konsentrasi Hg kecil, tetap harus diwaspadai karena sifatnya yang sulit tereliminasi. Konsentrasi logam dalam ikan biasanya menggambarkan besarnya konsentrasi Hg pada perairan tempat ikan berada. Hal ini sesuai karena konsentrasi rata-rata Hg dalam air pun sangat kecil ±1,79.10-6 mg/l yang nilainya jauh dari baku mutu yang ditetapkan PP RI no.82 tahun 2001 kelas III untuk perikanan, yaitu sebesar 0,002 mg/l. Dengan kondisi demikian maka ikan yang dibudidayakan di KJA dan ikan liar di Waduk Jatiluhur dianggap masih aman untuk dikonsumsi.Kata kunci: Akumulasi, keramba jaring apung, merkuri, Waduk Jatiluhur Abstract : Jatiluhur fish production have been suspected to contain dangerous chemicals because the water in reservoir allegedly contaminated by industrial waste and fish food itself, besides contamination from Citarum River?s and Cilalawi River?s pollution. This research was conducted to determine the mercury heavy metal contamination in water, fish cultured on cage aquaculture, and wild fish at Jatiluhur Reservoir. The species of fish samples were selected based on fish that mostly cultured at Jatiluhur Reservoir, such as Tilapia, Common Carp and Red Devil. From the examination it was known that the average Hg content in Red Devil, Common Carp, and Tilapia were 1.38.10-6; 1.74.10-6; 3.61.10-6 mg/kg, respectively. From those three species of fish that used for research, Hg concentrations from the highest were Red Devil > Common Carp > Tilapia. The highest concentration of Hg based on the organ sorted from the largest were gill > muscle > skin. Hg concentrations in fish were very small from standard quality 0.5 mg/kg defined by Head Regulation of Badan POM no. HK.00.006.1.524011. Even Hg concentrations were small, but its existence still had to be concern because Hg is difficult to be eliminated. Hg concenctrations in fish usually show Hg concencrations in water where fish lived. That was in accordance with the average concentration of Hg in water ±1.79.10-6 mg /l (very small) which value was far from the standard quality defined by PP R no.82 year 2001, class III for fisheries which was 0.002 mg/l. Under these conditions fish that cultured on cage aquaculture and wild fish at Jatilhur Reservoir were still safe for consumption. Key words: Accumulation, cage aquaculture, mercury, Jatiluhur Reservoir