Approximately one quarter of cancer patients are diagnosed with chronic insomnia, presenting as restlessness, trouble falling asleep and increased sleep-wake hours throughout the night. Sleep disturbances and deprivation negatively impacts the patient's quality of life, in terms of impaired mood, daytime fatigue, compromised immune function, and increased risk of depression. Pharmacological therapies often result in negative side effects. However, exercise is safe in a cancer population and has long demonstrated positive benefits in relation to improved treatment outcome. Purpose: As such, the purpose of this investigation was to examine the role of prescribed, individualized exercise in mitigating sleep disturbance associate with cancer treatment. Methods: This controlled trial evaluated the effects of individualized exercise therapy in 253 patients undergoing chemotherapy treatment. Study participants underwent standard prescribed chemotherapy schedules, and were excluded from the study if they had preexisting cardiac, liver, and bone marrow conditions prior to treatment. Each participant completed the Sleep Condition Indicator questionnaire at the start and conclusion of their treatment regimen. During their treatment, patients participated in a 12-week individualized, supervised exercise program through Maple Tree Cancer Alliance. An analysis of covariance (ANCOVA) was done to compare groups at each follow-up assessment using the baseline pre-chemotherapy measure as a covariate. A significance level of p< 0.05 was used for all statistical analyses. Results: Twelve weeks of prescribed, individualized exercise had a positive impact on fitness parameters, as well as sleep. Muscular strength, muscular endurance, and cardiovascular endurance significantly improved from baseline (average increases of 3.1 kg, 3.4, and 2.9 ml/kg/min, respectively. P<0.05). In addition, time to fall asleep, sleep quality, and early wake time were all significantly improved (average percent increases of 75.15%, 61.61%, and 160.61%, respectively. P<0.05). Conclusion: Twelve weeks of individualized exercise improved fitness parameters and mitigated symptoms of sleep deprivation and disturbance during chemotherapy treatment.