ReqView - Simple and powerful requirements management tool enabling easy requirements gathering, traceability tracking and offline collaboration.
rmtoo - rmtoo is a free and open source requirements management tool.
Jama Connect - The Leader in Requirements Management Solutions
Doorstop - Requirements management using version control.
Modern Requirements Suite4TFS - Modern Requirements Suite4TFS is an innovative, efficient and collaborative requirements management tool.
Traceable Requirement Management - Product Managers and Requirement Engineers need to efficiently capture and communicate the "voice of the customer", to enable their organization to deliver the right offers at the right time.