The purpose of this study was to examine the effect of board size, board composition, ownership concentration, managerial ownership, profitability on capital structure with quality of financial reports as mediator in manufacturing companies listed on the IDX. The sample are 25 companies with the 2015-2017 research year. The sampling technique uses purposive sampling. Data analysis techniques used descriptive statistics, classical assumption tests, multiple linear regression and sobel tests. The results is to indicate that board size, board composition, ownership concentration, ownership concentration, managerial ownership, and profitability has significant positive effects on quality of financial report, board size has significant negative effects on capital structure, board composition has significant positive effects on capital structure, ownership concentration has positive not significant effects on capital structure, managerial ownership has significant positive effects on capital structure, profitability has significant negative effects on capital structure, quality of financial reports has significant positive effects on capital structure, quality of financial reports is able to mediate board size, board composition, ownership concentration, managerial ownership, and profitability to capital structure. While quality of financial reports is not able to mediate managerial ownership to capital structure.