All medical enteral nutrition products contain phosphorus and when administered to patients with chronic kidney disease (CKD) and on dialysis, they lead to the risk of elevated serum phosphorus levels. Thus, serum phosphorus levels should be monitored, and phosphorus adsorbents should be used in cases of high serum phosphorus levels. In this study, we investigated the effect of phosphorus adsorbents on enteral nutrition, using Ensure Liquid, a medical nutritional formula, for patients with CKD and those on dialysis. Additionally, we compared the effects of the simple suspension method, in which various phosphorus-adsorbing agents are suspended and mixed directly with the nutritional formula for tube administration (hereafter referred to as the “pre-mix method”), and the conventional method, in which only the phosphorus-adsorbing agents are administered separately from the nutritional formula for tube administration (hereafter referred to as the “normal administration method”). The administration of various phosphorus adsorbents using the pre-mix technique resulted in a phosphorus removal rate of 8-15% (approximately 12% on average). Therefore, through the pre-mix method, maintaining the phosphorus content of Ensure Liquid below the daily phosphorus intake standard was possible for patients on dialysis. The pre-mix method via the simple suspension method of administering phosphorus adsorbent with Ensure Liquid resulted in less drug adsorption to the injector and tube and a higher phosphorus removal rate than the normal administration method.