BACKGROUND Little is currently known about predictors of follow-up outcome of psychological treatment of agoraphobia. In this study, we wished to examine predictors of short- and long-term avoidance after inpatient group interventions for agoraphobia. METHODS Ninety-six (68%) of 141 agoraphobic patients (74% women) who had completed treatment in two open and one randomized controlled trial (RCT) were followed up 13 to 21 years after start of treatment. RESULTS Major depression at pre-treatment predicted less short-term (up to one year after end of treatment) improvement in agoraphobic avoidance. Working and being married/cohabiting at pre-treatment predicted greater long-term (across one-year, two-year, and 13-21 years follow-up) improvement. In contrast, the duration of agoraphobia, amount of Axis I and II co-morbidity, being diagnosed with avoidant, dependent, and obsessive-compulsive personality disorder, and the use of antidepressants and benzodiazepines the month before intake to treatment, were unrelated to short-term as well as long-term outcome. LIMITATIONS As many as 31.9% of the included patients did not attend long-term follow-up and the power of the study was limited. The long time period between the two and 13-21 year follow-ups is a limitation, in which it is difficult to assess what actually happened. Although all the patients received some form of CBT, there was variability among the treatments. CONCLUSIONS The only short-term predictor identified represented a clinical feature, whereas the long-term predictors represented features of the patients' life situation. The limited power of the study precludes the inference that non-significant predictors are unrelated to follow-up outcome.