Aim Electrochemotherapy is an effective local treatment for cutaneous tumours and metastases. In this prospective trial, six European institutions investigated electrochemotherapy in recurrent, mucosal head and neck tumours. Patient and methods Forty-three patients with recurrent mucosal head and neck tumours and no further curative or reasonably effective palliative treatment options were enrolled and treated with electrochemotherapy. Patients were treated in general anaesthesia using intravenous or local injection of bleomycin followed by delivery of electric pulses to the tumour area. Primary end-point was local tumour response. Secondary end-points were safety and toxicity, overall and progression free survival, and quality-of-life. Results Thirty-seven patients were evaluable for tumour response, pain score, side-effects and quality of life questionnaires. Six patients were not evaluable due to lost follow-up, disease progression or death before evaluation. Intention to treat analysis revealed an objective response of 56% (complete response 8 (19%), partial response 16 (37%), stable disease 10 (23%), progressive disease 3 (7%), and not evaluable 6 (14%)). Three patients (7%) remained in complete response at 30, 34, and 84 months post-treatment. The treatment procedure was generally well tolerated. Swelling of the mucosa was observed in the first days after treatment. Pain and use of pain medication rose temporarily; fatigue and dysphagia were also noted in the quality of life assessment. Conclusion Electrochemotherapy can be applied to mucosal head and neck recurrent tumours accessible to the procedure with promising objective response, survival and toxicity profile. Attention should be paid to post-treatment swelling and planning of pain medication. These favourable results indicate that electrochemotherapy could play a role in patients with recurrent head and neck cancer.