This research dealt with the survey of the relationship among the transaction activity ratio and risk, return & portfolio diversification of mutual funds. the statistical population of this research consists of  investment managers of mutual funds and a sample of  investment managers of 37 mutual funds was investigated. Derived  results from analyzing the data by Pearson correlation and SPSS software show that between the transaction activity ratio of mutual funds and risk, return, portfolio diversification, there is a meaningful direct relation, meaningful reverse relation, meaningful reverse relation, respectively.
The results show that transaction activity ratio in men investment managers, less experienced, less educated and younger ones is more than women, more experienced, highly educated and older ones.
One of the findings of this research is the survey of relationship between mutual funds portfolio diversification ratio and transaction activity ratio of mutual funds which is done for the first time in Iran.