Historically, nursing education has recognized that writing enhances critical thinking, the basis of the clinical reasoning process. The online learning recently adopted by Nursing involves considerable writing, which may enhance critical thinking more than face-to-face courses. In the study reported here, the critical thinking and writing experiences of 34 registered nurses in an online course at an Ontario university were considered from several perspectives: perception of writing competence; demonstration of levels and kinds of critical thinking; and demonstration of writing competence. Although the participants' perceptions of their writing competence increased significantly, these results were not reflected in their levels of writing competence when compared to that of younger nurse-learners and students in an Arts course at the university. The study did not demonstrate that online writing results in different levels of critical thinking; it did, however, suggest a connection between and among online writing, different kinds of critical thinking, and assignment design. (Contains 2 figures and 5 tables.)