Purpose To determine the incidence of retinal detachment resulting from macular hole (MHRD) in fellow eyes. Design Observational case series. Methods The medical records of 59 normal fellow eyes of cases with MHRD diagnosed between 1994 and 2004 at Osaka Rosai Hospital were retrospectively reviewed. Thirty-nine of the 59 fellow eyes were highly myopic. The average follow-up period was 42 months with a range of seven to 132 months. The incidence of MHRD in fellow eyes, and the interval between the onset of MHRD in the first eye and the fellow eye were determined. The Kaplan-Meier method was used to estimate the probability of the fellow eye developing MHRD at 18 months and five years, and the probability of high myopia in the development of MHRD with log-rank test. Results Five eyes (8.5%) developed MHRD during the follow-up period. All affected eyes were highly myopic, and the incidence of MHRD among the highly myopic fellow eyes was 12.8%. The average interval was 51 months. The Kaplan-Meier estimated probability of the fellow eye developing MHRD was 3.7% (0% to 8.7% for 95% confidence interval [CI]) at 18 months and 8.0% (0% to 17.7% for 95% CI) at five years. The probability of the fellow eyes with high myopia developing MHRD was significantly higher than that of eyes without high myopia ( P = .0304). Conclusions The high incidence of MHRD developing in the fellow eye indicates that the fellow eyes should be examined and followed carefully.