Nutrition intervention by a registered dietitian nutritionist (RDN) is effective in improving patientsâ€™ knowledge or adherence to low-sodium diet (LSD, <2,000 mg/d); however, changes in knowledge and adherence in heart failure (HF) patients.Â Â have not been simultaneously assessed in the same study Therefore, the objective of the present study was to identify both HF patient sodium knowledge and adherence to the LSD before and after an education session with an RDN. A quasi-experimental study with a one-group, pre-test post-test design was conducted. An RDN conducted a 15-minute individualized nutrition education regarding the LSD at the initial visit. Sodium knowledge was measured by the Parkland Sodium Knowledge Test, and sodium intake was measured by a 29-item sodium-specific food frequency questionnaire created by NutritionQuestÂ© at both the initial and follow-up visits. A total of 71 patients were educated on the LSD and assessed for changes in sodium knowledge and intake at their next visit. Most patients were middle aged, obese, male, and non-Hispanic Black with an education level of greater than 12 years. At the initial visit, the majority of patients were considered knowledgeable but not accordant to the LSD. Following RDN education, sodium knowledge significantly improved and sodium intake significantly decreased. RDNs should be included as members of the HF multidisciplinary team to increase sodium knowledge and reduce sodium intake through individualized nutrition education.