The budget deficit has become a widespread phenomenon in most states of the world, as their demand and financing needs are often higher compared to the revenues obtained from taxes and fees. In this context, in the given article, the authors propose to analyze the theoretical and conceptual foundations of the budget deficit as an indicator of financial relations within the financial system, as well as its causes, consequences and sources of coverage. At the same time, the dynamics and evolution of the budget deficit of the Republic of Moldova, as well as their financing sources, will be analyzed. The research methodology related to the given article is represented by the method of analysis, synthesis, comparison, graphic method and data interpretation method, etc. As a result of the given research, the optimal methods of financing the budget deficit are to be identified as well as the situation of the budget deficit in the Republic of Moldova is to be analyzed.