This article develops and analyzes patient register-based measures of quality for the major Nordic countries. Previous studies show that Finnish hospitals have significantly higher average productivity than hospitals in Sweden, Denmark, and Norway and also a substantial variation within each country. This paper examines whether quality differences can form part of the explanation and attempts to uncover quality-cost trade-offs. Data on costs and discharges in each diagnosis-related group for 160 acute hospitals in 2008-2009 were collected. Patient register-based measures of quality such as readmissions, mortality (in hospital or outside), and patient safety indices were developed and case-mix adjusted. Productivity is estimated using bootstrapped data envelopment analysis. Results indicate that case-mix adjustment is important, and there are significant differences in the case-mix adjusted performance measures as well as in productivity both at the national and hospital levels. For most quality indicators, the performance measures reveal room for improvement. There is a weak but statistical significant trade-off between productivity and inpatient readmissions within 30 days but a tendency that hospitals with high 30-day mortality also have higher costs. Hence, no clear cost-quality trade-off pattern was discovered. Patient registers can be used and developed to improve future quality and cost comparisons.