Objective: To assess whether the cystic craniopharyngiomas can be controlled with the use of intratumoral applications of interferon alpha. Method: Nineteen patients with the diagnosis of cystic craniopharyngioma were treated with intratumoral chemotherapy with interferon alpha from January 2002 to April 2006. All patients underwent placement of an intracystic catheter connected to an Ommaya reservoir. Through this reservoir were made applications during chemotherapy cycles. Each cycle corresponded to application of 3,000,000 units of interferon alpha three times per week on alternate days totalizing 36,000,000 units. Response to treatment was evaluated by calculating the tumor volume on MRI control after one, three and six months after the end of each cycle. Patients who developed worsening of symptoms or who had insignificant reduction in tumor volume during follow-up underwent repeat cycle chemotherapy. Results: Four patients received four cycles of chemotherapy, three patients received three cycles, six patients received two cycles and six patients received one. The lower percentage of reduction in tumor volume was 60% and the bigger reduction was 98.37%. Eleven patients had a reduction greater than 90%. Five patients had a tumor reduction between 75 and 90% and in three patients the tumors were reduced by less than 75%. No deaths occurred during treatment and side effects of interferon alpha were well tolerated. No treatment was discontinued. Follow-up after the last application ranged from one year and five months to three years and nine months. Conclusion: The intratumoral chemotherapy with interferon alpha decreases the volume of cystic craniopharyngiomas and so far can be considered a new therapeutic alternative.