A questionnaire survey of 95 qualified psychotherapists of various therapeutic orientations and 69 psychologists in clinical training was carried out to investigate the main influences on their clinical practice, using the Questionnaire of Influencing Factors on Clinical Practice in Psychotherapies (QuIF-CliPP). For the qualified group the most highly rated factors were current supervision, client characteristics, client feedback, psychological formulation, intuition/judgement, professional training and post-qualification training. For the trainees, those rated highest were current supervision, past supervision, client characteristics, client feedback, psychological formulation and professional training. Evidence based factors such as treatment manuals and evidence based guidelines were rated relatively low for both groups, although the cognitive behaviour therapists rated them significantly higher than the other groups. Personal therapy was rated highly by the psychodynamic, psychoanalytic, person centred and eclectic therapists but not by CB therapists. The implications of these findings for the application of evidence based practice and the need to evaluated supervision, personal therapy and training are discussed.