The purpose of this final project is to know the internal control sytem of cash receipts and disbursements at PT Waskita Karya (Persero) Tbk, Batang Semarang Toll Road Projects Section 1-2. It is also to evaluate the effectiveness of the internal control system compared with the elements of internal control according to COSO. The first step in this case study was collecting the data through interview, observation, documentation, and library research. The next step was analyzing the data by applying descriptive qualitative method. The result showed that the internal control systems towards cash receipts and disbursements at PT Waskita Karya (Persero) Tbk, Batang Semarang Toll Road Projects Section 1-2 has been effective enough overall, but there are still parts of COSO elements that are not implemented yet. There are no separation of authority and responsibility between accounting department and cash retention. In the other side, there is no job rotation in the company so that the possibility of fraud is still very large. The recommended solutions as the result of this research are to separate the accounting department and cash retention, and to do the job rotation routinely