One of the important factors in making financial decisions is perceptual biases. They influence decisions at the time of exchanging stocks. The present research means to identify these common biases among investors and show its relation with their personality. Doing this research, the statistic society is considered unlimited thus a random group of 200 investors from Tehran stock exchange has been selected. The required data was collected by questionnaire. We have tried to test the authenticity of our hypotheses by using SPSS16 software. The findings of the research reveal that there is a meaningful connection between these biases and investors’ personality. The findings indicate that there is a direct correlation between extroversion and openness to experience and the bias of hindsight and overconfidence, between neuroticism and randomness bias, escalation of commitment and availability bias. There is a negative correlation between conscientiousness and randomness biases, between openness to experience and the bias of availability.