Background: Dysphagia is one of the most frequent side effects of chemo-radiotherapy for head and neck cancer, which has an adverse influence on the quality of life and health of survivors. Aim: This study aimed to evaluate the effectiveness of prophylactic swallowing exercise on dysphagia and quality of life among patients with head and neck cancer receiving chemo-radiotherapy. Method: A quasi-experimental research approach was conducted in radiotherapy department at Mansoura Nuclear Medicine Unit. Sample: A purposive sample of 60 head and neck cancer patients undergoing chemo-radiotherapy, was divided into two matched groups; study group and control group. Prophylactic swallowing exercise initiated before the start of chemo-radiotherapy and continued throughout the duration of their chemo-radiotherapy. Tools: A structured Interview Questionnaire, (EORTC) Quality-of-Life Questionnaire (QLQ-C30) and its Head and Neck Cancer Module (QLQH& N35) and Functional Oral Intake Scale (FOIS). Results: Head and neck cancer patients undergoing chemo-radiotherapy who received swallowing exercise experienced less dysphagia and improved quality of life compared to whom received routine care as there was a highly statistically significant differences between studied groups (p<0.001). Conclusion: Prophylactic swallowing exercise had a positive effect on dysphagia and quality of life in head and neck cancer patients undergoing chemo-radiotherapy. Recommendation: Head and neck cancer patients undergoing chemo-radiotherapy should be encouraged to perform the prophylactic swallowing exercise before and along the period of chemo-radiotherapy.