Despite growing emphasis on transitional care to reduce costs and improve quality, few studies have examined transitional care improvements in socioeconomically disadvantaged adults. It is important to consider these patients separately as many are high-utilizers, have different needs, and may have different responses to interventions. To evaluate the impact of a multicomponent transitional care improvement program on 30-day readmissions, emergency department (ED) use, transitional care quality, and mortality. Clustered randomized controlled trial conducted at a single urban academic medical center in Portland, Oregon. Three hundred eighty-two hospitalized low-income adults admitted to general medicine or cardiology who were uninsured or had public insurance. Multicomponent intervention including (1) transitional nurse coaching and education, including home visits for highest risk patients; (2) pharmacy care, including provision of 30 days of medications after discharge for those without prescription drug coverage; (3) post-hospital primary care linkages; (4) systems integration and continuous quality improvement. Primary outcomes included 30-day inpatient readmission and ED use. Readmission data were obtained using state-wide administrative data for all participants (insured and uninsured). Secondary outcomes included quality (3-item Care Transitions Measure) and mortality. Research staff administering questionnaires and assessing outcomes were blinded. There was no significant difference in 30-day readmission between C-TraIn (30/209, 14.4 %) and control patients (27/173, 16.1 %), p = 0.644, or in ED visits between C-TraIn (51/209, 24.4 %) and control (33/173, 19.6 %), p = 0.271. C-TraIn was associated with improved transitional care quality; 47.3 % (71/150) of C-TraIn patients reported a high quality transition compared to 30.3 % (36/119) control patients, odds ratio 2.17 (95 % CI 1.30-3.64). Zero C-TraIn patients died in the 30-day post-discharge period compared with five in the control group (unadjusted p = 0.02). C-TraIn did not reduce 30-day inpatient readmissions or ED use; however, it improved transitional care quality.