Abstract: Mass produced products are becoming more and more complex, which forces the designers to model the functionality early in the design process. UML Use cases was found to be a useful method for this purpose at Volvo Cars and is currently used for modeling all functions implemented in the electrical network. When using Use cases in design of complex safety critical systems there is still an uncovered demand for early hazard analysis at a functional level. This work integrates a modified Functional Hazard Assessment and Use cases. The analysis generates valuable results used as design requirements and dependability analysis input. The methods results have exceeded our expectations. An example is included in the paper, showing how the method works.