The primary purpose of this study was to determine whether well-designed instructional material based on motivational theory and blended learning theory has the intended impact on the learning motivation of adult learners in a distance education environment. This study used Voice-over-PowerPoint™ technology as a medium to deliver subject specific instruction based on motivational theory as supplementary content to the course curriculum. This empirical study was conducted over a period of approximately two months on a sample of 57 adult learners who were enrolled for a distance education course for non-degree purposes at a tertiary education institution. Quantitative research methods were applied and data was collected using two motivation-measuring surveys: (1) The Course Interest Survey; and (2) The Instructional Materials Motivation Survey, which were both developed by Keller. Motivational strategies were designed for the chosen educational technology, Voice-over-PowerPoint™ (VoP) videos, using Keller’s Attention, Relevance, Confidence and Satisfaction (ARCS) model of motivation. These strategies were then delivered via the learner management system for learners to use at their convenience. This research suggests that overall, learner motivation can be affected by external conditions such as well-designed instructional material, and further supports the ARCS model. Furthermore, the use of VoP videos as a viable medium for delivering motivational strategies in a blended, distance learning environment was validated.