BACKGROUND: The benefit of converting renal transplant recipients with gastrointestinal (GI) complaints from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) has not been evaluated using patient-reported outcomes. METHODS: A multicenter, open-label, prospective study was undertaken in MMF-treated renal transplant patients. Patients experiencing GI complaints were converted to equimolar EC-MPS (Cohort A). Patients without GI complaints remained on MMF (Cohort B). At baseline and Visit 2 (4-6 weeks postbaseline), patients completed the Gastrointestinal Symptom Rating Scale (GSRS), Gastrointestinal Quality of Life Index (GIQLI) and Psychological General Well-being Index (PGWBI). At Visit 2, patients and physicians completed the Overall Treatment Effect (OTE) scale for GI symptoms. Additionally, patients completed the OTE for health-related quality of life (HRQoL). Minimal important difference (MID) was calculated for GSRS and GIQLI based on patients’ and physicians’ OTE evaluation. RESULTS: Of 328 patients enrolled (i.e. the intent-to-treat and safety populations), 278 formed the per-protocol population (Cohort A, n=177; Cohort B, n=101). At baseline, Cohort A had significantly worse scores on all GSRS, GIQLI and PGWBI subscales compared to Cohort B (all P<0.0001). All GSRS, GIQLI and PGWBI subscale scores improved significantly in Cohort A between baseline and Visit 2 (all P<0.0001). Mean improvements in all GSRS subscales and most GIQLI subscores exceeded the calculated MID. GSRS, GIQLI and PGWBI subscales remained stable in Cohort B. CONCLUSION: This first exploratory study indicates that converting patients with mild, moderate or severe GI complaints from MMF to EC-MPS significantly reduces GI-related symptom burden and improves patient functioning and well-being.