In patients with Meniere's disease, the possibility of developing Meniere's disease in the uninvolved ear is of great concern. In this study, the incidence of bilateral Meniere's disease (BMD) in medically treated patients was found to be 17 percent, while in surgically treated patients it was significantly lower, 5.9 percent (p<0.01). The incidence of BMD for each surgical procedure was as follows: 9 percent after endolymphatic subarachnoid shunt (n=101), 7 percent after cochleovestibular neurectomy (n=100), 6 percent after cochleosacculotomy (n=18), and 0 percent after vestibular nerve section (n=73). The average duration of disease prior to surgery was 6.3 years. Seventy-two percent of the patients who developed BMD did so within 5 years of the onset of their symptoms. Proper patient selection is the most likely explanation for the low incidence of BMD among surgically treated patients.