Background. During military training, students in training schools undergo the Advanced Combat Course (ACC). This course is effective to obtain technical and tactical results for operations. However, there are physical results that cannot be evaluated by using a parameter, such as body mass index, making the understanding of the effects of the ACC on anthropometric conditions necessary to indirectly evaluate the course's components. These results can aid in making potential mid-or long-term adjustments so that training objectives are achieved, without detriment to the participants' well-being. Objective. This study's objective was to determine the anthropometric changes of the military personnel participating in the Advanced Combat Course and its significant physical repercussions, which can be used as an indicator of the improvement or not of the individual's physical fitness. Materials and methods. A longitudinal study was conducted with 69 military personnel (56 men and 13 women) in training at the Colombian Army's Escuela Militar de Cadetes. The participants signed an informed consent. An anthropometric assessment of height, weight, and waist circumference was performed before and after the ACC. Body composition was also evaluated using electrical bioimpedance (SECA 525), and the behavior of the data was established by using the SPSS Ver. 21 statistical program. The statistical significance of the data was then established by using Student's t-test method for paired data. Results. The varia-Characterizing the fitness of Colombian military personnel bles of WEIGHT, body mass index (BMI), relative fat mass (RFM), absolute fat mass (AFM), visceral adipose tissue (VAT), extracellular fluid (ECF), and phase angle (PhA) had statistically significant changes, meaning that the ACC's physical burden produces changes on these variables. There were no statistically significant changes in the fat-free mass (FFM), skeletal muscle mass (SMM), total body water (TBW), and waist circunference (WC). Conclusions. While the physical load involved in the 8-week advanced combat course produces changes in all the anthropometric variables evaluated through bioelectrical impedeance analysis, only a few variables present statistically significant changes. However, they are unproved concerning fat-free mass, skeletal muscle, total water, and waist circumference.