This study aims to determine the factors influencing the level of IPO Underpricing on companies listed on the Indonesian stock exchange from 2015 to 2017. Variables examined include Return on asset, firm age, financial leverage, number of shares offered, and auditor reputation. This research is carried out by analyzing multiple regression with a 5% significance level. Observation and literature study with purposive sampling is used as the data collection method. The study concluded that ROA and the number of shares offered show a significant positive effect on underpricing. Firm age, financial leverage, and auditor reputation do not significantly influence underpricing.