Abstract Introduction: Constraint-induced movement therapy (CIMT) is a very modern method used in rehabilitation to treat individuals with functional impairment of the upper limbs. Objective: To apply the CIMT method and evaluate its effects in a patient with ataxia after removal of a cerebellar tumor. Method: This is a longitudinal interventional study of the case report type. The participant complained of tremors and difficulty writing and typing with the right hand as a result of the cerebellar tumor’s removal. She was subjected to CIMT daily in three-hour sessions for 10 days. The participant was evaluated with the Motor Activity Log (MAL) and the Wolf Motor Function Test (WMFT). Results: There was an improvement in the quantity, quality, speed, accuracy and strength with which the participant performed the tasks according to the MAL and WMFT scales. Improvement in writing was also identified and the report of better use of the member for daily tasks demonstrated the patient’s satisfaction after the end of therapy. Conclusion: This case report demonstrated the benefits of the application of the CIMT method in a patient with ataxia as a consequence of a rare cerebellar tumor, improving task execution time, strength and functional improvement of the affected upper limb.