All studies indicate that over half of an average data processing user staff is committed to maintaining existing applications. However, as opposed to software development where productivity is measured in terms of lines of code, function-points, data-points or object-points per person month and quality is measured in terms of deficiencies and defect rates per test period, there are no established metrics for measuring the productivity and quality of software maintenance. This means that over half of an organization's software budget cannot be accounted for. The costs occur without being able to measure the benefits obtained. A set of metrics is proposed for helping to remedy this situation by measuring the productivity and quality of the maintenance service.