Introduction: Tinnitus is a common symptom among patients with sensorineural hearing loss. Electrical stimulation may induce or suppress auditory sensation temporarily. The cochlear implant is one of the presently available methods of electrical stimulation which may change the tinnitus sensation. Objective: To investigate the frequency of occurrence of tinnitus in patients with bilateral profound sensorineural hearing loss who underwent a multichannel cochlear implantation in our service, as well as its evolution after the establishment of electrical stimulation. Methods: The authors interviewed all patients who underwent cochlear implantation from April 1999 to November 2001, searching for the tinnitus characteristics before and after the surgery. Patients living out of Brazil or without a minimum linguistic code to understand the questions were excluded from the study. There were 21 patients in the final evaluation. Results: Tinnitus was present in 13 cases (61,9%) before the cochlear implantation. Two months after the constant use of the implant, tinnitus presented significant improvement in 8 cases (61,5%), did not change in 3 (23,1%) and worsened in 2 cases (15,4%). Among the 8 patients without tinnitus before implantation, none developed the symptom after the surgery. Conclusions: Our results point out that the cochlear implant may be a useful tool in the tinnitus control in patients with profound sensorineural hearing loss with surgical indication.