OBJECTIVES This presentation expands on a previous ISPOR presentation on patient acceptance of the use of Mixed Modes for collecting PROs in trials. The ISPOR PRO Mixed Modes task force recommends when mixing modes to avoid mixing paper with ePRO. However, interest in using paper for PRO collection still exists. This presentation will investigate survey data to examine if patients prefer ePRO over paper. METHODS The research (conducted in 2013) includes patients globally (N=405) who participated in at least one clinical trial requiring patient diaries in the past two years. Patients were asked about previous diary experiences and future trial participation. The previous presentation showed most patients are in favor of mixed modes–mainly due to being able to choose their preferred mode. This presentation focuses on patients with prior experiences with both paper and ePRO (N=167). RESULTS Of paper/ePRO experienced patients, 77.3% preferred ePRO; 76.1% had high agreement that ePRO makes dairy participation easier; 73.1% had high agreement that ePRO-use makes them more willing to participate in future diaries. Of patients who prefer ePRO, those who used ePRO in their most recent trial had significantly higher satisfaction ratings (87.0%) than those who used paper (55.2%), p<0.001. Low agreement ratings were associated with dissatisfaction and longer times per diary entry. CONCLUSIONS These findings show most patients prefer ePRO and satisfaction rates are higher when patients use their preferred ePRO mode. Sponsors should consider using ePRO due to patient preference, as higher satisfaction is associated with optimal compliance and data quality when implemented appropriately. As lower agreement was associated with dissatisfaction and longer times per entry, this indicates there may have been issues with ePRO implementation or instrument selection. Proper implementation planning should include appropriate ePRO mode/instrument selection, ensuring ease of use while keeping patient burden low and satisfaction high.