ABSTRACT: Objective:We sought to measure patient portal satisfaction with patient portals and characterize its relationship to attitude towards computers, health literacy, portal usage, and patient demographics. Materials and Methods:We invited 13 040 patients from an academic medical center to complete a survey measuring satisfaction, perceived control over computers, and health literacy using validated instruments (End User Computing Satisfaction, Computer Attitude Measure, and Brief Health Literacy Screen). We extracted portal usage and demographic information from the medical center data warehouse. Results:A total of 6026 (46.2%) patients completed the survey. The median (IQR) scores for satisfaction, computer control, and health literacy were 87% (20%), 86% (22%), and 95% (15%), respectively. The normalized mean (SD) usage of messaging, lab, appointment, medication, and immunization functions were 6.6 (2.6), 4.6 (2.4), 3.1 (1.7), 1.5 (1.2), and 0.88 (0.91) times, respectively. Logistic regression yielded significant odds ratios [99% CI] for computer control (3.6 [2.5-5.2]), health literacy (12 [6.9-23]), and immunization function usage (0.84 [0.73-0.96]). Discussion:Respondents were highly satisfied and had high degrees of computer control and health literacy. Statistical analysis revealed that higher computer control and health literacy predicted higher satisfaction, whereas usage of the immunization function predicted lower satisfaction. Overall, the analytical model had low predictive capability, suggesting that we failed to capture the main drivers of satisfaction, or there was inadequate variation in satisfaction to delineate its contributing factors. Conclusion:This study provides insight into patient satisfaction with and usage of a patient portal. These data can guide the development of the patient portal, with the ultimate goal of increasing functionality and usability to enhance the patient experience.