This graduation thesis will present the impact and usefulness of sensitivity and probability analysis when planning an investment project. An investment can be considered as any kind of expense, primarily of monetary resources in order to achieve certain economic benefits, respectively profit, most often measured by cash flows as expressions of economic, i.e. usable income. Cash flows, which are defined as cash receipts that the project achieves, or as cash expenditures that are necessary to ensure the creation of cash receipts, also have a great influence when choosing a project. With every entrepreneurial project, it is important to present to all interested parties a sufficient number of quality indicators for the degree of future effectiveness and profit efficiency, that is, a presentation of dynamic and static method indicators. Furthermore, the break even point of the project is aimed at finding the balance point, that is, the business level at which the project generates neither profit nor loss. The implementation of investment projects is associated with a greater or lesser degree of risk and uncertainty. This is exactly the role of the sensitivity analysis to determine the extent to which the project is sensitive to changes in variables that have an impact on the final evaluation results. While on the other hand, probability analysis shows the ranges of possible values of critical parameters, as well as their probability of occurrence.