Research has shown that psychological skills training can be effective in enhancing athletes?performance and positively influencing cognitive and affective states (cf. Williams & Krane, 2001). However, to date, little work has been conducted inves¬tigating such processes with adolescent high-performing swimmers. The present study examined the effects of a seven-week psychological skills training (PST) pro¬gram on competitive swimming performance and positive psychological development. Thirty-six national level swimmers (13 boys, 23 girls; M = 13.9 years old) followed a PST program for 45 minutes per week. The intervention consisted of goal setting, visualization, relaxation, concentration, and thought stopping. Performance times were obtained from official meets. Participants completed seven inventories measuring quality of performance, and six positive psychological attributes: mental toughness, hardiness, self-esteem, self-efficacy, dispositional optimism, and positive affectivity. Findings demonstrated that there was a significant post-PST program improvement in three separate swimming strokes, each over 200 m. Non-significant improvements were shown in 10 other events. There was also an overall significant improvement in participants?post-intervention positive psychological profiles.