Patients miss about 20% of scheduled appointments for mental health treatment, almost twice the rate in other medical specialties. Up to 50% of patients who miss appointments drop out of scheduled care. Many who miss appointments because of slips and lapses later rearrange their appointments without adverse consequences. Those that do not are at risk of further deterioration, relapse and hospital readmission. Predictors of non-attendance are complex and linked with the predictors of missed medication. Service barriers and administrative errors are common but are often overlooked in the absence of feedback from patients. Of prime importance are the therapeutic alliance and degree of ‘helpfulness’ of the clinician but again these are rarely measured routinely. Useful markers of engagement include patient-rated trust, satisfaction and degree of perceived participation in treatment decisions. Much can be done to improve attendance in most services. Simple measures such as offering prompt, convenient appointments, offering reminders and augmenting with telephone contact have a reasonable evidence base. Scales to assess therapeutic alliance are now available. Complex interventions need to be evaluated carefully in order that the overall benefits outweigh costs. We suggest that clinicians consider accessibility, discharge policies and patient feedback when examining local rates of non-attendance.