In answer to calls for research about professional change, this study addressed the question: What is involved in college science faculty readiness for change in instructional practice? The setting was a professional development experience in oceanography/marine science and paleoclimatology among 32 faculty from 2- and 4-year colleges. Ten of the 32 participated in interviews, and all provided survey responses and documents used in the study. Cycles of inductive analysis generated three example case stories to illustrate a new model for exploring faculty readiness for change in teaching. The model blends results from the health sciences on readiness for behavioral change with research on the personal, external, professional, and consequence domains of a professional change environment. The blended model attends to how an instructor draws on the domains to (a) see an instructional challenge as requiring intentional action to be resolved; (b) notice new significance (for the instructor) in some aspect of instructional practice; (c) feel able to manage instructional stressors/challenges; (d) have commitment to initiate/sustain change; and (e) perceive adequate support in undertaking change. Profiles of instructional readiness for change are represented by composite cases named Lee, Pat, and Chris. In the case of Lee, factor (c) drove change efforts; for Pat, factors (a) and (b) were in the forefront; and for Chris it was factors (d) and (e). The three cases are valuable both as sketches of the blended model in use and as touchstones for future research and development related to postsecondary faculty professional learning.