rmtoo - rmtoo is a free and open source requirements management tool.
Visure - Visure offers a flexible , modern and complete requirements ALM Platform (Application Lifecycle Management).
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.
ReqView - Simple and powerful requirements management tool enabling easy requirements gathering, traceability tracking and offline collaboration.
Requirements Quality Suite - The Systems Engineering Suite offers you the tools, processes and skills to Verification, Traceability, Reusability and Quality.
Jama - Jama combines requirement management software with enterprise collaboration capabilities to solve product delivery problems.