iarjbmIARJBMIARJBM2708-5147https://doi.org/10.47310/iarjbm.2020.v01i01.015The Effect of Company Size and Sales Growth on Capital Structure with Profitability as Mediation in Construction and Building Sub-Sector Companies Registered in Indonesia Stock ExchangeDewiRoozanaZulkifliAbdulRivaiSuhartoThis study aims to determine the effect of company size and sales growth on capital structure with profitability as mediation in construction and building sub-sector companies listed on the Indonesia Stock Exchange (IDX). The research population is companies in the construction and building sector which are listed on the Indonesia Stock Exchange. The sampling technique used was purposive sampling, namely construction and building companies that published complete financial reports from 2014-2018. The results showed that company size did not have a significant effect on profitability. The sales growth variable does not partially affect profitability. The firm size variable does not partially affect the firm structure. The sales growth variable does not partially affect the company structure. The capital structure variable does not partially affect profitability. The direct effect of firm size on capital structure is 0.266. While the influence of company size through profitability is 0.218 x 0.285 = 0.062. This shows that the direct effect is greater than the indirect effect so that the profitability variable is not a mediating variable because its existence does not increase the effect of firm size on capital structure. Meanwhile, the effect of sales growth on profitability is 0.254. Meanwhile, the effect of sales growth on the capital structure through the profitability variable is 0.325 x 0.285 = 0.0926. This effect is smaller than the direct effect of 0.254. So, the profitability variable is not a mediating variable because its existence does not increase the influence of growth on the capital structure.