Summary:Background: Congenital venous malformations are frequently treated with sclerotherapy. Primary treatment goal is to control the often size-related symptoms. Functional impairment and aesthetical aspects as well as satisfaction have rarely been evaluated. Patients and methods: Medical records of patients who underwent sclerotherapy of spongiform venous malformations were reviewed and included in this retrospective study. The outcome of sclerotherapy as self-reported by patients was assessed in a 21 item questionnaire. Results: Questionnaires were sent to 166 patients with a total of 327 procedures. Seventy-seven patients (48 %) with a total of 159 procedures (50 %) responded to the survey. Fifty-seven percent of patients were male. The age ranged from 1 to 38.1 years with a median age of 16.4 years. The lower extremities were the most common treated area. Limitations caused by the venous malformation improved in the majority of patients (e.g. pain improvement 87 %, improvement of swelling 83 %) but also worsening of symptoms occurred in a minority of cases. Seventy-seven per cent would undergo sclerotherapy again. Conclusions: Sclerotherapy for treatment of venous malformations results in signifi cant reduction of symptoms. Multiple treatments are often needed, but patients are willing to undergo them.