In financial investment decisions to be made by individual investors, it is highly important that they should be aware of the possibility of facing with psychological biases by knowing their own personality traits and should consider their own financial risk tolerances. In this study, the relation between personal traits, psychological biases and financial risk tolerance of inverstors were tested through a questionnaire. Sample of the study were selected among individual inverstor who live in İstanbul and operate in financial markets. The hypotheses made within the scope of the study were tested by chi-square analysis and logistic regression analysis. As a result of the hypotheses testing, it was concluded that there was a significant relation between the personality traits of investors and the psychological biases they faced and that the personality traits of investors affected their financial risk tolerances.