Abstract: Carlson, MJ and Jaenen, SP. The development of a preselection physical fitness training program for canadian special operations regiment applicants. J Strength Cond Res 26(7): S2–S14, 2012—Special Operations Forces (SOF) soldiers must undergo a rigorous selection process that requires high levels of physical fitness and stamina to complete. Physical preparedness is crucial for an applicant's performance during a selection process; preselection physical training programs for SOF applicants must be specific to the demands of the selection process. The purpose of this study was to analyze the physical demands of the Canadian Special Operations Regiment (CSOR) Assessment Center (AC) to develop an evidence-based physical fitness program to assist future applicants to CSOR with their physical preparation. Seventy-one men volunteered to undergo a battery of fitness tests before attending the CSOR AC. Forty-six (mean [SD]: age 26.2 [4.4] years, height 176.5 [7.4] cm, body mass 82.4 [10.1] kg) of the 71 participants further volunteered to participate in the characterization of the physical demands of the AC. Heart rate (HR) data were collected during the physically demanding sessions, and a subsequent task and physiological analysis was conducted to determine key performance variables for exercise prescription. The physically demanding sessions ranged in length from 26.38 (4.24) minutes to 668.52 (30.09) minutes, with the mean HR data ranging from 169.81 (6.64) to 97.51 (6.65) b·min−1, respectively. Key predictors of completion of the AC were V[Combining Dot Above]O2peak (βexp: 5.92; confidence interval [CI]: 1.1–31.0), and 1-repetition maximum (1RM) squats (βexp: 5.16; CI: 1.2–22.2). The information derived from this study provided the foundation for the design of an evidence-based preparatory training program for future applicants that is reflective of the physical demands of the selection process.