The purpose of this study is to review the effect of hosting on performance of host countries in summer and winter Olympic Games. Statistical population is all multi sport competitions of IOC comprising winter and summer Olympic Games. Statistical sample is performance of all countries that be host in this games (48 countries) comprising of 27 hosts in summer games and 27 hosts in winter games. The data related to each competition is gathered from books, papers, dissertations and related websites. Relative share of total medals and count of obtained medals is used as a proxy for countries performance. For reviewing the performance in host and guest situation, the relative share of total medals/count of obtained gold medals that gained by host country is compared with relative share of total medals/count of obtained gold medals that gained by this country in periods other than host period. Descriptive and inferential statistics (Kolmogorov-Smirnov and Wilcoxon tests) is used for analyzing data. The results show no meaningful difference between relative share of total medals and count of gold medals in host guest situations in both of summer and winter Olympic Games. Finally, countries with hosting request and home advantage not only will develop political, economic, cultural, environmental, tourism and psychological aspects, but it will have higher performance in terms of medals.
