Jurnal Sosio-Religia LinkSas Yogyakart, Vo. 9, No. 2 tahun 2010 1 PERILAKU KONSUMEN MUSLIM DALAM MEMAKSIMUMKAN KEPUASAN M. Nur Rianto Al Arif Fakultas Syariah dan Hukum UIN Syarif Hidayatullah Jakarta Abstract Two concept of the consumers behavior theory that already been developed in conventional economics is economic rationality and utilitarianism. Indifference curve is a tool to analysis about utility maximize in consumer behavior theory, but this maximize theory has a boundary that called by budget constraint. In Islamic economics, the boundary of Moslem consumer to maximize utility is not enough only by budget constraint but also added by shariah principle. This boundary called by budget and shariah constraint. The position of budget and shariah constraint is below of budget constraint in conventional economics. Keyword: consumer behavior, indifference curve, budget and shariah constraints