Background: Postgraduate medical education is undergoing a paradigm shift in many universities worldwide, transitioning from a time-based model to competency-based medical education (CBME). Residency programs might have to alter clinical rotations, educational curricula, assessment methods, and faculty involvement in preparation for CBME, a process not yet characterized in the literature. Methods: We surveyed Canadian medical oncology program directors on planned or newly implemented residency program changes in preparation for CBME. Results: Prior to implementing CBME, all program directors changed at least 1 clinical rotation, most commonly making hematology/oncology (74%) entirely outpatient and eliminating radiation oncology (64%). Introductory rotations were altered to focus on common tumour sites, and later rotations were changed to increase learner autonomy. Most program directors planned to enhance resident learning with electronic teaching modules (79%), new training experiences (71%), and academic half-day changes (50%). Most program directors (64%) planned to change assessment methods to be entirely based on entrustable professional activities. All programs had developed a competence committee to review learner progress, and most (86%) had integrated academic coaches. Conclusions: Transitioning to CBME led to major structural and curricular changes within medical oncology training programs. Identifying these commonly implemented changes could help other programs transition to CBME.