BACKGROUND: Having investigated the decision making of world class elite and subelite athletes (see Parkin and Walsh, 2017; Parkin et al., 2017), here the abilities of those at the earliest stage of entry to elite sport are examined. Junior elite athletes have undergone initial national selection and are younger than athletes examined previously (mean age 13 years). Decision making under mental pressure is explored in this sample. During performance an athlete encounters a wide array of mental pressures; these include the psychological impact of errors, negative feedback, and requirements for sustained attention in a dynamic environment (Anshel and Wells, 2000; Mellalieu et al., 2009). Such factors increase the cognitive demands of the athletes, inducing distracting anxiety-related thoughts known as rumination (Beilock and Gray, 2007). Mental pressure has been shown to reduce performance of decision-making tasks where reward and loss contingencies are explicit, with a shift toward increased risk taking (Pabst et al., 2013; Starcke et al., 2011). Mental pressure has been shown to be detrimental to decision-making speed in comparison to physical stress, highlighting the importance of considering a range of different pressures encountered by athletes (Hepler, 2015). OBJECTIVE: To investigate the influence of mental pressure on key indicators of decision making in junior elite athletes. This chapter concludes a wider project examining decision making across developmental stages in elite sport. The work further explores how psychological insights can be applied in an elite sporting environment and in particular tailored to the requirements of junior athletes. METHODS: Seventeen junior elite athletes (10 males, mean age: 13.80 years) enrolled on a national youth athletic development program participated in the study. Performance across three categories of decision making was assessed under conditions of low and high mental pressure. Decision making under risk was measured via the Cambridge Gambling Task (CGT; Rogers et al., 1999), decision making under uncertainty via the Balloon Analogue Risk Task (BART; Lejuez et al., 2002), and fast reactive responses to perceptual stimuli via the Visual Search Task (Treisman, 1982). Mental pressure was induced with the addition of a concurrent verbal memory task, used to increase cognitive load and mimic the distracting effects of anxiety-related rumination. RESULTS: In junior elite athletes, fast reactive responses to perceptual stimuli (on the Visual Search Task) were slower under conditions of mental pressure. For decision making under risk there was an interaction of mental pressure and gender on the amount of points gambled, under pressure there was a higher level of risk taking in male athletes compared to females. There was no influence of mental pressure on decision making under uncertainity. There were no significant correlations in the degree to which individual’s responses changed under pressure across the three measures of decision making. When assessing the applicability of results based on group averages there were no junior elite athletes who showed an “average” response (within 1SD of the mean) to mental pressure across all the three decision-making tasks. CONCLUSION: Mental pressure affects decision making in a sample of junior elite athletes, with a slowing of response times, and modulations to performance of decision making under risk that have a high requirement for working memory. In relation to sport, these findings suggest that novel situations that place high cognitive demands on the athlete may be particularly influenced by mental pressure. The application of this work in junior elite athletes included the feedback of individual results and the implementation of a decision-making taxonomy.