Phosphate binder compounds contribute to the control of hyperphosphatemia in hemodialysis (HD) patients. However, the most effective schedule of administration of phosphate binders in relation to meals is not well documented. We examined the effectiveness of aluminum hydroxide intake as the sole phosphate binder in relation to meals. Eighty-five patients on regular HD (45 male, 40 female), age 21-72 years, with a duration of 6-216 months HD participated in the study. In all patients, phosphate binders were discontinued for a one month period. Thereafter, and according to the protocol, all patients were advised to take aluminum hydroxide [Al(OH)3 ] 30 min before, during and 30 min after meals for 3 periods of one month each, in a random order. One month washout period preceded the periods of Al(OH)3 ingestion. When Al(OH)3 was administered 30 min prior to the meals, serum phosphate decreased by 7.0% (0.59 mg/dL), while when administrated with or 30 min after meals, it decreased statistically significantly by 28.5% (2.08 mg/dL), and 16% (1.29 mg/dL) respectively. Our results suggest that the efficacy of Al(OH)3 to bind phosphate salts and thus to prevent the hyperphosphatemia in HD patients is higher when this drug is taken with meals.