Two feeding trials were carried out to investigate apparent nutrient digestibility of flounder fed experimental diets containing different levels of macro-nutrients by satiation feeding rate (Exp-1) and feeding frequency (Exp-2). Triplicate groups of fish averaging 280 g were fed three experimental diets which contained different levels of carbohydrate, protein and lipid by two feeding regimes (satiation and 80% satiation) and four feeding frequencies (three meals a day, two meals a day, one meal a day and one meal every two days). Feces were collected using a fecal collection column attached to fish rearing tanks for 6 weeks. Apparent digestibilities of dry matter, protein, lipid, energy and carbohydrate were not affected by feeding satiation rate in Exp-1. Apparent protein digestibility was not affected by feeding frequency, whereas affected by dietary composition in Exp-2. Apparent protein digestibility of fish fed a high-protein diet showed a tendency to become higher compared to that of fish fed high-carbohydrate diet and high-lipid diet at the same feeding frequency. Apparent lipid digestibility was not affected by dietary composition, however, affected by feeding frequency. Apparent digestibilities of energy and carbohydrate were affected by both dietary composition and feeding frequency. Apparent digestibities of energy and carbohydrate in fish fed the high-protein diet showed a tendency to become higher compared to that of fish fed the high-carbohydrate diet and high-lipid diet at the same feeding frequency. Apparent digestibities of energy and carbohydrate tended to decrease with increasing of feeding frequency at the same dietary composition.