The aim of the present study was to investigate whether body composition and engagement in an exercise program\ud influenced participants’ physical self-perceptions. The study consisted of 92 participants, 40 males and 52 females; with an average age of 31.9± 9.37 years. The Physical Self-Perception Profile was used to assess physical self-perceptions(PSPP; Fox & Corbin, 1989). Body fat percentage was measured using a bioelectrical impedance analyser (RJL systems,Detroit). In addition, height,weight, BMI and WHR was assessed. The study consisted of an exercise intervention group (N = 72) and a control group (N = 20). Participants in the intervention group attended public gyms in North-west London.Measurements were taken at the induction session and after a 10 week intervention period. All participants were provided with an individual training program which followed the ACSM guidelines. Adherence was assessed by means of an electronic entry card to the gym facilities and a self-report measure.\ud For statistical analysis the participants in the exercise\ud group were categorised as either adherers (> 30 sessions; N = 35), and non-adherers (< 30 sessions; N= 26). Repeated\ud measures analysis of variance [3 (adherers, non-adherers, control) x 2 (pre-, post-test)] and follow-up post-hoc\ud comparisons showed that the adherers had a significant decrease in % body fat and BMI and a significant increase on the body, condition and strength subscales of the PSPP\ud from pre- to the post-test.Additionally, correlational analysis for the change in the dependent variables from pre- to post-test showed only significant correlations for the adherers. The participants who adhered to the exercise program showed significant changes in their body composition\ud in terms of a decrease in % body fat and BMI and this change was associated with perceiving oneself in better physical condition, and stronger. They were also more satisfied with their physique. These findings partially support Fox’s (1997) intervention hypothesis in that engaging in regular physical exercise and its associated physical changes can positively alter participants’ physical self-perceptions.\ud