Background Hyperphosphatemia is a frequently encountered and difficult-to-manage problem in hemodialysis (HD) patients and is an important risk factor for cardiovascular diseases. This study was carried out to explore the effect of nutritional education on the serum phosphorus level in HD patients. Patients and methods This open-label, single-center randomized controlled trial involved 100 HD patients. Patients were randomly assigned to one of two groups: the education group underwent a 12-week nutritional education program, whereas the control group received standard treatment. Nutritional education was provided by a trained renal dietitian in the form of educational sessions, brochures, audiovisual teaching aids, and patient-tailored dietary recommendations. Detailed nutritional and laboratory tests were done before randomization and 3 weeks after the end of the study. Results Serum phosphorus level and calcium–phosphorus product were significantly lower among the education group (P=0.02 and 0.04, respectively) with a percent reduction of serum phosphorus of -13.8 ± 21.41 after nutritional education. Nutritional education (B: -0.57, 95% confidence interval: -1.13 to -0.01, P=0.04) and the dietary protein intake (B: -0.47, 95% confidence interval: -0.94 to -0.003, P=0.04) were the predictors of serum phosphorus level at the end of the study. Three weeks after termination, BMI, waist circumference, and malnutrition inflammation score were lower (P=0.04, 0.04 and 0.02, respectively), whereas midarm muscle circumference was higher (P=0.004) among the education group. Conclusion Nutritional education can help in controlling the serum phosphorus level in HD patients without causing derangements in the nutritional status and should be provided in each HD unit.