A study was conducted on fish marketing system to find out different marketing channels, marketing cost, and margins of fish at different intermediaries in Moulavibazar district, Northeast Bangladesh. It was carried out from August 2012 to July 2013 in six markets through questionnaires method. A large number of intermediaries were involved in fish marketing channel as aratdar (commission agent), paiker (wholesaler) and retailer. Seven marketing channels were identified. Paiker or bepari (wholesaler) brought fish from producer and finally sold fish to retailer through aratdar with commission. In some cases producer bought fishes to arat (wholesale market). Total marketing cost of producer, aratdar, paiker and retailer were Tk. 8.47±0.225, 1.39±0.284, 10.99±0.467 and 3.21±0.186 kg-1 of fish, respectively. Total marketing costs for different intermediaries were Tk. 24.05kg-1 fish in Moulavibazar district. During peak period, (i.e., November to January) average net profit of aratdar, paiker and retailer were Tk. 3.48±0.072, 3.32±0.059 and 6.142±0.075 kg-1 fish, respectively. During lean period (April to July), average net profit of aratdar, paiker and retailer were Tk. 4.06±0.079, 3.65±0.073 and 7.14±0.08 kg-1 fish, respectively. Net margin of intermediaries during peak and lean period were Tk. 4.31 and 4.95kg-1 fish, respectively. This study explores important information about the sustainable and effective fish marketing system in Moulavibazar and other areas of the country.