The thesis explores the relationship between salivary testosterone (T), cortisol (F), and non-physical competition in women. In order to address widely acknowledged difficulties with determining levels of female T, particularly the biologically active ‘free’ fraction as measured in saliva, a highly sensitive ‘in-house’ enzyme-linked immunosorbant assay (ELISA) was optimised and validated. Assay sensitivity was 0.5pg/mL. By determining a comprehensive picture of the daily activity of salivary T in 34 healthy female subjects, it was possible to demonstrate that T follows a circadian rhythm the relative levels of which differ over two non-consecutive days. Moreover, throughout the course of the day T levels were highly variable, with episodic fluctuation of individual data points exceeding 83% of 9am levels. A quasi-experimental study examined changes in T and F in relation to non-physical dyadic encounters. Twenty-four females (ages 19-24 years) competed in a knockout tournament involving the wood-block game ‘Jenga’. They collected comprehensive salivary samples for baseline, pre- and post-competition phases. Subjects additionally reported mood states and answered questions concerning their participation in the competition. Whilst the comprehensive T data resist easy interpretation, compared against baseline, pre-comp T appeared un-responsive in anticipation of competition even though F levels did rise in the 3 hours prior to competition. Compared with levels immediately pre-competition, 1 hr post-competition T levels were higher in winners than losers. F-levels, conversely, rose in losers and fell in winners. These results illustrate that, similar to males, women demonstrate a dynamic endocrine response to competition. Moreover, choice of competitive task and salivary sampling regimens may, to a large extent, account for the equivocal findings in the literature.