Men who have sex with men (MSM) and transgender women (TGW) in the United States face a high burden of HIV, but the uptake of preexposure prophylaxis (PrEP) remains low. With long-acting injectable PrEP, now with Food and Drug Administration-approved and newer formulations entering clinical use, our study developed attributes for a discrete choice experiment to capture PrEP access preferences in Baltimore. Nested within a mixed method project, five focus groups (21 MSM and two TGW) informed attribute development using a four-step framework: data collection, thematic coding, attribute reduction, and refinement. Guided by the Gelberg-Andersen model and a systematic review, 50 themes were reduced to six attributes. Choice sets were pilot tested with nine participants. The six attributes were modality/effectiveness, side effects, provider environment, dispensing location, support monitoring, and cost/insurance. Pilot testing confirmed usability. This rigorous, community-informed process produced attributes, reflecting structural and personal factors influencing PrEP decision making, now integrated into a cross-sectional survey to guide equitable service delivery.