This paper presents the course of action and outcome of a teacher-based action research project concerning development and evaluation of an online introductory biology course for non-majors. The research took place in a small community college and compared online and traditional instructional formats. A course was developed in an entirely web-centered format. After a semester of instruction, participants were assessed with a 50 item multiple choice test pertaining to content knowledge gained in the course. When their scores were compared with students taught in a traditional classroom format, the scores were essentially identical. The research format may serve as a model for teachers who wish to explore the issue of web-based instruction in their own practice. (Contains 3 figures and 1 table.)