Insider trading activity is investigated prior to merger announcement in Indian capital market. An attempt is made to check it out whether trading takes place on the basis of asymmetric and private information. For examining the behaviour of stock prices a modified market model is used to estimate the parameters for the estimation window. These estimates are used to compute average return and cumulative average returns for the event window, which are measures of abnormal returns. Besides price run-ups, it is also common to see unusually high levels of share trading volume before public announcement of merger. Daily trading volume pattern of the target companies is also investigated. The analysis carried out in this study is based on a sample of 42 companies for which merger announcement date was announced during the period of 1996-1999. Based on the analysis for each company individually, we recommend investigation in six companies for existence of possible insider trading.