Objective. To investigate equity of patient outcomes in a psychological therapy service, following increased access achieved by a quality improvement (QI) initiative. Design. Retrospective service evaluation of health outcomes; data analysed by ANOVA, chi-squared and Statistical Process Control. Setting. A psychological therapy service in Westminster, London, UK. Participants. People living in the Borough of Westminster, London, attending the service (from either healthcare professional or self-referral) between February 2009 and May 2012. Intervention(s). Social marketing interventions were used to increase referrals, including the promotion of the service through local media and through existing social networks. Main Outcome Measure(s). (i) Severity of depression on entry using Patient Health Questionnaire-9 (PHQ9). (ii) Changes to severity of depression following treatment (ΔPHQ9). (iii) Changes in attainment of a meaningful improvement in condition assessed by a key performance indicator. Results. Patients from areas of high deprivation entered the service with more severe depression (M = 15.47, SD = 6.75), com-pared with patients from areas of low (M = 13.20, SD = 6.75) and medium (M = 14.44, SD = 6.64) deprivation. Patients in low