Background: Cisplatin administration may induce muscle atrophy, thereby reducing the fitness level of patients with head and neck cancer (HNC). To date, only animal studies have been conducted to test the effectiveness of exercise interventions in diminishing side effects of cisplatin. Aim: To determine whether exercise training improves physical fitness and health-related quality of life (HRQoL) in patients receiving chemotherapy for Head & Neck (H&N). Material and methods: This pilot-randomized controlled trial was conducted on 57 participants receiving chemotherapy for HNC. The participants were randomized into an exercise group and a control group. The exercise group received moderate-intensity combined aerobic, resistance and flexibility exercises three times a week for eight weeks during chemotherapy. The control group received no specific information regarding exercise. The outcome measures including body composition, muscle strength, balance, flexibility, cardiovascular fitness and health-related quality of life (HRQoL) were assessed at baseline and eight weeks following baseline. Results: The body composition (body fat percentage, p = 0.002; skeletal muscle percentage, p = 0.008), dynamic balance (p = 0.01), muscle strength (upper extremity, p = 0.037; lower extremity, p = 0.025) and HRQoL (p = 0.001) showed a significant difference between the exercise group and the control group eight weeks following baseline. Significant deteriorations were noted in flexibility, muscle strength, cardiovascular fitness and several domains of HRQoL scale in the control group at eight weeks following baseline. Conclusions: This study found that a combined aerobic, resistance and flexibility exercise program during chemotherapy may improve physical fitness (i.e., muscle strength, balance, flexibility and body composition) and HRQoL and alleviate the deterioration of cardiovascular fitness in patients with HNC. Further research studies with large sample sizes are warranted to investigate the long-term effects of exercise in this population.