OBJECTIVES: Patients’ perceptions of products used for testosterone replacement therapy (TRT) may vary according to product attributes such as application site, duration of use and physical qualities. The objective of this study was to assess the domains associated with the preference for TRT products, to identify salient themes and attributes, and to develop a patient-reported outcomes (PRO) instrument for use in clinical trials. METHODS: The study used a standard qualitative approach to develop a theoretical framework and to identify items and develop themes from a set of attributes associated with TRT product use and preference. Items and themes gleaned from a literature review and expert opinion were used to develop a theoretical framework and a discussion guide. This guide was used by trained researchers to interview patients, who were experienced using TRT and voluntarily agreed and consented to participate in the research study using IRB-approved documents. Results from telephone interviews were transcribed using NVivo 9 qualitative analysis software (QSR International, Cambridge, MA) and classified according to TRT themes.  Demographic and other data collected through the interview process were entered into a spreadsheet for descriptive analysis. RESULTS: The saturation of items and exhaustion of themes was accomplished by 58 male patients with an average age of 55.0±1.3 years (22-69).  Patients used TRT for an average of 183±40.5 days, with approximately 50% of patients having experience with more than one form of TRT. Five patients participated in cognitive debriefing. The study revealed 8 themes: ease of use, libido, preference, product characteristics, physiological impact, psychological impact, side effects, and treatment experience. CONCLUSIONS: Themes and items related to TRT use were in concordance with the theoretical framework developed in the study.  The PRO instrument can be further developed for potential use in clinical trials.