Recent discoveries about the role of microorganisms in the establishment of the geological conditions in the planet have lead to the development of courses in Geomicrobiology. Unfortunately, most courses are designed for students with a strong Geology background, which is a limitation for universities that lack such courses. To overcome this limitation at our university, we have designed a special topics course entitled Introductory Geomicrobiology that was offered for the first time to undergraduate students from the Biology, Marine Biology and Microbiology Programs. To attract non-geology majors the course included topics such as description of Early Earth ecosystems, search for geo-biological signatures and current approaches in the search for extra-terrestrial life forms. An active learning environment was fostered throughout the course through different activities including oral reports of research papers in the subject, followed by Gallery Runs and class discussions. Our assessment strategies, both formative and summative, revealed that such presentations were an effective way to introduce students to eight main concepts of Geomicrobiology. Student performance was stronger in group discussions than individually, with Gallery Runs as the preferred class discussion technique. Overall, our assessment system proved that the design of the course was effective in teaching Geomicrobiology to nongeology majors.