ABSTRAK Telah dilakukan penelitian tentang sebaran klorofil-a dan kualitas air di muara Sungai Krueng Aceh dan Lamnyong, Banda Aceh. Tujuan penelitian ini adalah untuk mengetahui konsentrasi klorofil-a, serta untuk mengetahui hubungan antara parameter fisik kimia dan konsentrasi klorofil-a di kawasan perairan muara Sungai Krueng Aceh dan Lamnyong. Pengambilan sampel dilakukan pada bulan Februari 2016. Metode yang digunakan ditentukan secara purposive sampling. Pengambilan sampel dilakukan pada 3 stasiun di tiap lokasi penelitian. Hasil penelitian menunjukkan adanya hubungan antara parameter fisika kimia dengan konsentrasi klorofil-a. Konsentrasi klorofil-a di muara sungai Lamnyong berkisar antara 0 – 0,31 µg/l, nilai tertinggi ditemukan di stasiun 1 (muara sungai) dengan nilai sebesar 0,31 µg/l, dan nilai terendah di stasiun 2 dan 3 sebesar 0 µg/l. Konsentrasi klorofil-a di muara sungai Aceh berkisar antara 0 – 1,39 µg/l, nilai tertinggi terdapat di stasiun 1 dengan nilai sebesar 1,39 µg/l, dan yang terendah terdapat di stasiun 2 sebesar 0 µg/l. Berdasarkan nilai klorofil yang diperoleh dapat disimpulkan bahwa perairan Sungai Krueng Aceh dan Lamnyong tergolong kedalam perairan yang bersifat oligotrofik. Kata Kunci: Klorofil-a; Sungai Krueng Aceh; Sungai Krueng Lamnyong ABSTRACT Research on the distribution of chlorophyll-a and water quality at Krueng Aceh River and Lamnyong River, Banda Aceh. The purpose of this study was to determine the concentration of chlorophyll-a, as well as to determine the relationship between the chemical and physical parameters of chlorophyll-a concentration in Krueng Aceh and Lamnyong River estuary waters. Sampling was conducted February, 2016. The method used is the puposive sampling. Samples were collected at three stations in each study sites. The results showed that an association between physical and chemical parameters with a concentration of chlorophyll-a. The concentration of chlorophyll-a in Lamnyong estuaries range from 0 - 0.31 µg/l. The highest concentration were found at Station 1 (embouchure) with a value of 0.31 µg / l, and the lowest concentration at station 2 and 3 at 0 µg/l, and the concentration of chlorophyll-a in Aceh estuaries range from 0 - 1.39 µg/l, the highest concentration found at station 1 with a value of 1.39 µg/l, and the lowest was in the station 2 at 0 µg/l. Therefore, the waters of Krueng Aceh River and Lamnyong River were classified into the oligotrofik waters. Keywords : Chlorophyll -a; Krueng Aceh River; Krueng Lamnyong River.