The aim of this study was to better understand care protocol implementation, including the influence of organizational-contextual factors on implementation approaches, in long-term care homes operating in Ontario. We surveyed directors of care employed in all 547 Ontario LTC homes, and combined survey data with secondary organizational data on rural/urban location, nursing home size, chain membership, type of ownership, and accreditation status. Motivations for the use/selection of care protocols in nursing homes primarily derived from beliefs in continuous improvement and in evidence-based care. Protocol selection was largely participative, involving management and staff. External information sources were important for protocol implementation, and in-service education was the chief means of training and educating staff. Significant differences in approaches to implementation were evident in association with differences in ownership. Three key success factors for implementation were identified: contextualizing the practice change, adequately resourcing for implementation, and demonstrating connections between practice change and outcomes.