Background: Older people with common mental health problems (CMHPs) are known to have reduced rates of referral to psychological therapy. Aim: We aimed to assess referral rates to the Improving Access to Psychological Therapies (IAPT) service, contact with a therapist and clinical outcome by age. Design and Setting: Empirical research using patient episodes of care from South West IAPT. Method: By analysing 82,513 episodes of care (2010-2011), referral rates and clinical improvement were compared to both total population and estimated prevalence in each age group using IAPT data. Probable recovery of those completing treatment were calculated for each group. Results: Estimated prevalence of CMHPs peaks in 45–49 year olds (20.59% of population). The proportions of patients identified with CMHPs being referred peaks at 20-24 years (22.95%) and reduces with increase in age thereafter to 6.00% for 70-74 year olds. Once referred, the proportion of those attending first treatment increases with age between 18 years (57.64%) and 64 years (76.97%). In addition, the percentage of those having a clinical improvement gradually increases from the age 20 years (12.94%) to 69 years (20.74%). Conclusion: Younger adults are more readily referred to IAPT services. However, as a proportion of those referred, probabilities of attending once, attending more than once, and clinical improvement, increase with age. It is uncertain whether optimum levels of referral have been reached for young adults. It is important to establish whether changes to service configuration, treatment options, and GP behaviour can increase referrals for middle-aged and older adults.