Research has demonstrated that active learning, spaced education, and retrieval-based practice can improve knowledge acquisition, knowledge retention, and clinical practice. Furthermore, learners prefer active learning modalities that use the testing effect and spaced education as compared to passive, lecture-based education. However, most research has been performed with students and residents rather than practicing physicians. To date, most continuing medical education (CME) opportunities use passive learning models, such as face-to-face meetings with lecture-style didactic sessions. The aim of this study was to investigate learner engagement, as measured by the number of CME credits earned, via two different learning modalities. Diplomates of the American Board of Anesthesiology or candidates for certification through the board (referred to colloquially and for the remainder of this article as board certified or board eligible) were provided an opportunity to enroll in the study. Participants were recruited via email. Once enrolled, they were randomized into 1 of 2 groups: web-app-based CME (Webapp CME) or an online interface that replicated online CME (Online CME). The intervention period lasted 6 weeks and participants were provided educational content using one of the two approaches. As an incentive for participation, CME credits could be earned (without cost) during the intervention period and for completion of the postintervention quiz. The same number of CME credits was available to each group. Fifty-four participants enrolled and completed the study. The mean number of CME credits earned was greater in the Webapp group compared to the Online group (12.3 ± 1.4 h versus 4.5 ± 2.3 h, P < .001). Concerning knowledge acquisition, the difference in postintervention quiz scores was not statistically significant (Webapp 70% ± 7% versus Online 60% ± 11%, P = .11). However, only 29% of the Online group completed the postintervention quiz, versus 77% of the Webapp group (P < .001), possibly showing a greater rate of learner engagement in the Webapp group. In this prospective, randomized controlled pilot study, we demonstrated that daily spaced education delivered to learners through a smartphone web app resulted in greater learner engagement than an online modality. Further research with larger trials is needed to confirm our findings.