The purpose of this paper is to investigate evidence of the market volatility of Bursa Malaysia as a result of insider trading activities. The study used insider trading data of Bursa Malaysia sourced from Bloomberg, Singapore and I-capital Malaysia. The insider transactions involve filing made to Bursa Malaysia from 1 July 2003 to 30 June 2008. The number of insider transactions totaled 5799 and originates from 70 KLCI component stocks. This study uses the GARCH model to evaluate the effect of insider trading on market volatility of Bursa Malaysia. The sum of alpha and beta from the GARCH results are computed to assess volatility persistency. The study indicates that 38% of insider trades influences and affects market volatility. Knowing that insider trading is a criminal offence under the Malaysian security laws, in general 62% of insiders will ensure that their trading does not affect the volatility of the market. Insiders might disguise their trading with stock pooling and friendly syndicates. A pattern has emerged in Bursa Malaysia that stock prices drop more violently, stock prices drop more than going up and there is a tendency for stock prices to drop more often. With this general observation, insiders will go for piggy-backing on insider trades and trading intensity.