Background: In recent years, preventive swallowing exercises have been investigated as a means to limit dysphagia in head and neck cancer patients. However, adherence to exercise regimes has been poorly documented limiting the conclusions drawn on the effects of the interventions. We investigated adherence to a preventive swallowing exercise program and identified possible associations between adherence and four selected baseline factors: HPV status, partner status, concomitant chemotherapy and tumor site and between adherence to swallowing exercises and attendance to supervised training sessions. Material and methods: Forming part of an ongoing RCT (clinicaltrials.gov NCT02385929) adherence to intervention was based on participant provided training-logs. The exercise program consisted of 3 weekly supervised sessions of 30 min each and a home-based exercise program to be performed three times daily. Adherence was calculated as percentage of prescribed exercises completed and dichotomously as high (≥80%∼median) and low (<80%∼median) adherence. Associations between adherence and clinical/demographic factors (HPV, partner status, chemotherapy, tumor site or attendance level) were explored by logistic regression analyses. Results: Full adherence data were available from 45 (76%) participants. The total cohort median adherence to exercises was 78%. No association was found between any of the tested factors and adherence. Discussion: The study found a high adherence to preventive swallowing exercises in HNC patients undergoing (chemo)radiotherapy, both in home-based exercises and in supervised sessions, when compared to other studies, although median adherence to home-based exercises was below the defined 80% threshold. We acknowledge, that adherence in an RCT may be higher than in the everyday clinical situation due to surveillance bias. However, we find it reassuring that HNC patients comply with a preventive swallowing program, which requires some time investment from the patients.