Income smoothing is one of the ways used by management to reduce fluctuations in earnings obtainedin order to profit in accordance with the desired target. This study aimed to test: the effect of firm age,firm size, and firm profitability on income smoothing on companies listed in the Indonesia StockExchange. The sample is determined based on purposive sampling, a total of 265 manufacturingcompanies during the 2010-2014 period. Technical analysis of the data using logistic regression. Theresults showed that the age of the firm, firm size, and profitability influence the practice of incomesmoothing.Keywords: Firm Age, Firm Size, Firm Profitability, Income Smoothing