The budgets of state-owned companies account for two-thirds and sometimes three-fourths of the public and annual budget, and this huge amount will not be scrutinized by the parliament and the Court of Audit during the review and approval phase. In other stages, we do not see effective monitoring. Therefore, the article with a descriptive and analytical method seeks to answer the question of how effective legislative oversight of the budget of state-owned companies can be applied and what harms it faces. The research findings confirm the claim that there are various types of a posteriori and a priori parliamentary oversight in different stages of the budget, from intensifying government oversight when preparing companies' budgets to the time of consideration and approval in the parliament and after its implementation. Removal of obstacles and attention to the following will be effective. Issues such as paying serious attention to macro-policies in the field of privatization and reducing the number of state-owned companies as one of the roots, formulating a comprehensive law to structurally reform companies' budgets, changing the classification category and clarifying their financial performance.