The current article examines the influence of cognitive biases on the process of decision making among equity investors of India. The research is being directed by conducting a survey on a sample of 400 investors investing in Indian capital market. This study measures behavioural biases of individual investors' using a structured questionnaire as a research instrument of the study. By means of cross section data analysis, this analysis steadily provides evidence that behavioural biases adversely affect rational decision-making of an investor. This research indicates that a statistically significant relationship exists between behavioural biases among investors and the process of rational decision-making. The findings of the study are imperative to investors investing Indian capital... market, brokers, financial consultants and investment advisors; responsible for managing assets and constructing portfolios for investment clients, as they can alter the investment decision by accessing the susceptibility of investors towards cognitive biases, which often lead to erroneous decision.