Background Early mobility interventions in the intensive care unit can improve patients’ outcomes, yet they are not routinely implemented in many intensive care units. In an effort to identify opportunities to implement and sustain evidence-based practice, prior work has demonstrated that understanding the decision-making process of health professionals is critical for identifying opportunities to improve program implementation. Nurses are often responsible for mobilizing patients, but how they overcome barriers and make decisions to mobilize patients in the intensive care unit is not understood. Objective To describe processes that nurses in intensive care units use to make decisions and barriers that influence their decision-making about patient mobility. Methods An exploratory descriptive approach using semi-structured interviews of a purposive sample of registered nurses in 2 intensive care units at 2 hospitals was used. Interviews were transcribed and analyzed by using directed content analysis to identify categories that describe nurses’ decision-making about patient mobility. Results Semistructured interviews were conducted with 20 nurses in a 1-on-1 setting. Four main categories that influenced nurses’ decision-making about mobility were identified in the directed content analysis: purpose of mobility, gathering information, establishing and activating the plan, and barriers to progressing the plan. Conclusions Deciding to mobilize patients in the intensive care unit is a multifaceted, individualized decision made by nurses, and numerous patient-, nurse-, and unit-related factors influence that decision. Future studies that target unit culture and interprofessional perspectives are needed.