Workflow technology promises an increase in efficiency in the execution of business processes. The technology is widely accepted, but often the high costs exceed the promised benefits. Thus, it is desirable to calculate the profitability prior to investing into workflow technology. After an investment into workflow management systems (WFMS), it has to be verified whether the expected benefits have been realized or not. In this paper we present a method that covers both, the cost-benefit-ratio calculations specially customized for WFMS and the calculation of the realized savings. The profitability analysis is based on simple measurable performance indicators that consider the tangible calculation of costs as well as the quantitative and qualitative benefits. Long time practical experience in implementing and operating workflow management supported the design of the method. The method presented in this paper has been successfully used in the IT company of a banking corporation.