Rationale & Objective: Patients with chronic kidney disease (CKD) are particularly sensitive to dietary sodium. We evaluated a self-management approach for dietary sodium restriction in patients with CKD. Study Design: Randomized controlled trial. Setting & Participants: Nephrology outpatient clinics in 4 Dutch hospitals. 99 adults with CKD stages 1 to 4 or a functioning (estimated glomerular filtration rate ≥ 25 mL/min/1.73 m2) kidney transplant, hypertension, and sodium intake >130 mmol/d. Intervention: Routine care was compared with routine care plus a web-based self-management intervention including individual e-coaching and group meetings implemented over a 3-month intervention period, followed by e-coaching over a 6-month maintenance period. Outcomes: Primary outcomes were sodium excretion after the 3-month intervention and after the 6-month maintenance period. Secondary outcomes were blood pressure, proteinuria, costs, quality of life, self-management skills, and barriers and facilitators for implementation. Results: Baseline estimated glomerular filtration rate was 55.0 ± 22.0 mL/min/1.73 m2. During the intervention period, sodium excretion decreased in the intervention group from 188 ± 8 (SE) to 148 ± 8 mmol/d (P < 0.001), but did not change significantly in the control group. At 3 months, mean sodium excretion was 24.8 (95% CI, 0.1-49.6) mmol/d lower in the intervention group (P = 0.049). At 3 months, systolic blood pressure (SBP) decreased in the intervention group from 140 ± 3 to 132 ± 3 mm Hg (P < 0.001), but was unchanged in the control group. Mean difference in SBP across groups was −4.7 (95% CI, −10.7 to 1.3) mm Hg (P = 0.1). During the maintenance phase, sodium excretion increased in the intervention group, but remained lower than at baseline at 160 ± 8 mmol/d (P = 0.01), while it decreased in the control group from 174 ± 9 at the end of the intervention period to 154 ± 9 mmol/d (P = 0.001). Consequently, no difference in sodium excretion between groups was observed after the maintenance phase. There was no difference in SBP between groups after the maintenance phase. Limitations: Limited power, postrandomization loss to follow-up, Hawthorne effect, lack of dietary data, short-term follow-up. Conclusions: A coaching intervention reduced sodium intake at 3 months. Efficacy during the maintenance phase was diminished, possibly due to inadvertent adoption of the intervention by the control group. Funding: Grant funding from the Netherlands Organization for Health Research and Development and the Dutch Kidney Foundation. Trial registration: Registered at ClinicalTrials.gov with study number NCT02132013.