An important step to software developing is the system functional requirements elicitation. Business process models can be adopted as source to extraction of functional requirements during the information system modeling. Commonly, functional requirements are documented in use case diagrams or textual use cases. This paper provides an approach to derive use case specification from BPMN models. This specification is described as UML Use Case diagram and textual natural language. This approach is supported by a tool - BP2UC (Business Process to Use Cases) - which performs the guidelines described in the approach. The proposed approach and tool showed feasibility since they provided useful results for the next steps of the software process.