Oliver, JM, Abt, JP, Sell, TC, Beals, K, Wood, DE, and Lephart, SM. Salivary hormone response to 12-week block-periodized training in naval special warfare operators. J Strength Cond Res 29(1): 66–73, 2015—Naval Special Warfare (NSW) Operators are expected to maintain a high degree of physical readiness requiring continual operational training. The physiological and psychological demands associated with operational training can result in physiological consequences evidenced by hormonal alterations justifying the need for periodized training to maintain or improve physical readiness. This study examined the pattern and time course of hormone changes during 12-week block-periodized training program (BP) in NSW Operators undergoing routine training. Eighteen NSW Operators (31 ± 6 years, 86.6 ± 9.0 kg, 176.2 ± 5.9 cm, 17.5 ± 6.5% fat) participated in a 12-week BP during routine operational training. Salivary free testosterone (FT), dehydroepiandrosterone sulfate (DHEA-S), and cortisol (C) were obtained at 4 time points coincident with changes in intensity and volume. In the second block of training in which intensity and volume were increased, FT and C increased by 20.3 ± 7.4 and 20.8 ± 9.9%, respectively. Free testosterone and C returned to baseline values concomitant with the decrease in intensity and volume at the conclusion of the third block of training. No significant differences were observed in FT-to-C ratio over the course of training. DHEA-S increased 23.1 ± 11.0% following block 1, with a further increase observed following block 2 (57.0 ± 17.4%). Our data indicate training following BP produces a pattern and time course of hormone changes congruent with changes in intensity and volume suggesting BP as a potential training model for NSW Operators and other Special Forces Operators involved in operational training.