This paper describes the use of cognitive-behavioural therapy to assist a very experienced Special Olympics tennis player control his unacceptable on-court behaviour. In 10 weekly sessions he was taught to relax both on and off court, change his gloomy self statements and negative predications of his future behaviour, analyse and learn three essential elements of good sporting behaviour and practised these skills under low stress conditions. He assisted in the writing of a book, which described all the stages of his therapy, and he looked at the book often between therapy sessions. At an interstate championship held 3 months later the player won all his early matches but lost in the final series. However he was able to practise relaxation skills and positive self-statements, and perform all the elements of good sporting behaviour.