This paper examines the existence of behavioural finance aspects among Malaysian fund managers. We identify behavioural biases of loss aversion, disposition effect and illusion of control. We also study the endowment effect and mental accounting which rooted in the Prospect Theory. We developed two-parts experiments i.e. investment-related decisions and general behavioural questions. The study revealed that Malaysian fund managers are prone to behavioural biases in investment decisions and general aspects as well. We also analysed the data in comparison with demographical information such as age, gender, years of experience and investing style. We find that the younger fund managers tend to experience behavioural biases more than the elders. Female fund managers prone to loss aversion and disposition effect than male fund managers, while male fund managers experience a moderately higher percentage in illusion of control than the female counterpart.