This study was conducted with the background that many companies did earning management through transactionswith a related party in Initial Public Offering (IPO). This study aimed to examine the influence of relatedparty transaction about earnings management in IPO. The population in this study was companies listed inIndonesia Stock Exchange. The sampling method used for this study was purposive sampling. This study used38 samples from non-financial firms that conducted IPO's in the Indonesia Stocked Exchange in 2009-2011.PairedSample t-test was used to examine the significant earnings management which was represented by ROA. Multiplelinear regression used RP Sales, RP Purchases, and RP Liabilities to the effect of earnings management. Theresult of this study showed that there was no a significant change between ROAt=-1 and ROAt=0 IPO period.The related party sales transaction did not have a significant effect of earnings management. However, this studyindicated that the related party purchases transaction had a significant negative effect and related party liabilitiestransaction had a significant positive effect on earnings management.