This paper describes key issues in conducting impact evaluations of corporate eLearning and reports the results of a study that evaluated the impact (including return on investment) of an eLearning implementation by a large telecommunications company. The program was designed to "multi-skill" over 1,000 Customer Service Officers (CSOs) using custom-designed eLearning courses that provided coaching as an integral element. The two critical business objectives of this initiative were to save training costs and to reduce training time. More were realized. The following factors that must be considered when designing an impact evaluation for corporate eLearning are described: evaluation decisions, issues and questions; elapsed time; sample; instruments and techniques; data collection; interpretation of results; secondary benefits; data for the future; and who conducts the evaluation. (Author/AEF)