Quality and performance concerns have increased dramatically over the last ten years in the automotive industry. Demands on bearing steel internal quality as a means of improving bearing performance have reflected this trend. Meaningful measures of internal quality were vital to promote improvement, and SAM ratings of microinclusions were developed partly to serve this purpose. In addition, AMS 2301 magnetic particle inspection procedures were applied to measure macroinclusions. Cooperative work with numerous steelmakers led to significant cleanliness improvement as measured by these tools. Ongoing laboratory testing of thousands of bearings over the past seven years shows continuous bearing performance improvement attributable to many factors, among which internal steel quality plays a significant role. The internal laboratory bearing test data are also confirmed by long-term field performance as determined by a mathematical model, taking into account total bearings in the field, accumulated service, service sales, and service inventories. This model is in turn confirmed by failure mode analysis of failed components retrieved from the field.