♦ Introduction: Young children and infants with chronic kidney disease are at increased risk of hyperphosphatemia because of high intake of dairy products. Hyperphos phatemia leads to metastatic calcifications and an increased risk of cardiovascular complications. Sevelamer is an effec tive phosphate binder, but for children it has important practical disadvantages: it clogs enteral feeding tubes and can cause gastrointestinal complaints. Pretreatment of dairy products to reduce their phosphate content might solve those problems. ♦ Methods: Sevelamer hydrochloride and sevelamer carbon ate were suspended in various dairy products (cow's milk, breast milk, baby formula, and tubefeeding formula). Each product was tested with varying concentrations of sevelamer. After suspension, each sample was stored for 10 minutes, allowing the sevelamer to precipitate. The supernatant was decanted and analyzed for pH and for phosphate, calcium, magnesium, potassium, sodium, and chloride content. ♦ Results: We observed a significant decrease in the phosphate content of all tested products. With sevelamer hydrochloride, the phosphate reduction was 48% -91% in the various products, and with sevelamer carbonate, it was 22% -87%. The highest effectiveness was found in breast milk. A pH increase was found in all products. With sevelamer hydrochloride, a significant increase in chloride occurred. Notably, a significant decrease in calcium content (-75%) was observed in treated breast milk. ♦ Conclusions: Pretreatment of a variety of dairy products with either sevelamer hydrochloride or sevelamer carbon ate effectively reduced their phosphate content and might avoid troublesome ingestion of sevelamer in children. The change in pH with sevelamer hydrochloride was remark able, reflecting buffering mechanisms. The reduction in the calcium content of breast milk is a potential concern and should be carefully considered and monitored during clinical use of sevelamer.