People with decompensated cirrhosis are often prescribed a complex regimen of therapeutic and prophylactic medications. In other chronic diseases, polypharmacy increases the risk of medication misadventure and medication-related problems (MRPs), with associated increased morbidity, mortality, and health care costs. This study examined MRPs in a cohort of ambulatory patients with a history of decompensated cirrhosis who were enrolled in a randomized controlled trial of a pharmacist-led, patient-oriented medication education intervention and assessed the association between MRPs and patient outcomes. A total of 375 MRPs were identified among 57 intervention patients (median, 6.0; interquartile range, 3.5-8.0 per patient; maximum 17). Nonadherence (31.5%) and indication issues (29.1%) were the most prevalent MRP types. The risk of potential harm associated with MRPs was low in 18.9% of instances, medium in 33.1%, and high in 48.0%, as categorized by a clinician panel using a risk matrix tool. Patients had a greater incidence rate of high-risk MRPs if they had a higher Child-Pugh score (incidence rate ratio [IRR], 1.31; 95% confidence interval [CI], 1.09-1.56); greater comorbidity burden (IRR, 1.15; 95% CI, 1.02-1.29); and were taking more medications (IRR, 1.12; 95% CI, 1.04-1.22). A total of 221 MRPs (58.9%) were resolved following pharmacist intervention. A greater proportion of high-risk MRPs were resolved compared to those of low and medium risk (68.9% versus 49.7%; P < 0.001). During the 12-month follow-up period, intervention patients had a lower incidence rate of unplanned admissions compared to usual care (IRR, 0.52; 95% CI, 0.30-0.92). Conclusion: High-risk MRPs are prevalent among adults with decompensated cirrhosis. Pharmacist intervention facilitated identification and resolution of high-risk MRPs and was associated with reduced incidence rate of unplanned hospital admissions in this group.