Lockie, RG, Orr, RM, Stierli, M, Cesario, KA, Moreno, MR, Bloodgood, AM, Dulla, JM, and Dawes, JJ. The physical characteristics by sex and age for custody assistants from a law enforcement agency. J Strength Cond Res 33(8): 2223-2232, 2019-Custody assistants (CAs) are a position within a law enforcement agency who are responsible for assisting officers with maintaining security in correctional facilities. Unlike other positions, CAs may not be required to complete physical testing before being hired. This lack of testing could influence the characteristics of CAs who attend academy training. Therefore, retrospective analysis of performance test data for 108 officers (69 men and 39 women) was conducted. The tests included: grip strength for both hands; number of push-ups and sit-ups in 60 seconds; 201-m (220 yard) and 2.4-km runs; and maximal aerobic capacity (VO2max) estimated from the 2.4-km run. Data were stratified by sex and age (≤24 years, 25-29 years, 30-34 years, and ≥35 years). Independent samples t tests (p ≤ 0.05) calculated differences between men and women. To compare age groups, a 1-way analysis of variance with Bonferroni post hoc was used (p ≤ 0.05). Men scored significantly higher than women in hand grip, push-ups, and sit-ups, were faster over the 201-m and 2.4-km runs, and had a higher Vo2max (p ≤ 0.001-0.024). There were no significant differences in performance tests across the age groups for either men or women. To better tolerate the rigors of physical training, female CAs should attempt to improve their fitness before the start of academy training because they often need to complete the same tasks as the male CAs. Age did not seem to influence the physical characteristics of CAs, although all CAs should attempt to develop the fitness qualities needed for their occupation.