This paper traces the evolution of the ASTM Test Monitoring Center (TMC) from its modest beginnings in 1976 to the present. Formed as an unbiased and non-aligned group within ASTM Subcommittee D02.B, the TMC operates a reference oil based calibration system that serves both the producers and users of automotive lubricants. Governed by the ASTM Test Monitoring Board, the center's primary mission is to calibrate engine dynamometer test stands used to conduct various ASTM test methods for evaluating lubricant performance. The core services of the TMC have remained the same over its nearly 25 year history. The center stores and distributes ASTM reference oils and is responsible for assuring, through the use of analytical testing, the quality and consistency of the oils. The number of reference oils handled by the TMC has steadily increased over time such that today the center inventories some 100 different formulations having a total volume of 65,000 gallons. Lubricant performance tests conducted using reference oils generate a large database that the TMC maintains on its computer servers. These data are the basis for calibrating test stands and for tracking the precision and bias of ASTM test methods. The sophistication of TMC data analysis has evolved from simple hand plotting of results to the use of complex statistical methods, including quality control charting techniques. Reference oil test data, coded to conceal the oil suppliers, are readily available to industry stakeholders via the TMC Internet web site. The number of test methods under TMC surveillance has grown from six engine dynamometer tests to 30+ methods that now include two-stroke cycle, gear rig, and analytical bench tests. TMC engineers conduct periodic laboratory audits to check for compliance with published test procedures. The center assists in ASTM standards development through the issuance of information letters that provide timely modifications to test methods. The list of TMC services has increased over the years in response to the changing needs of the industry. Accordingly, the center has grown from a staff of two with an annual budget of $150,000 to its present staff of 18 with a $2,000,000 budget. The Test Monitoring Board (TMB) remains committed to ensure the continued financial stability of the TMC in order that it may continue to provide valueadded services into the future.