With the advancement of web services technologies, on-line businesses have the ability to offer their capabilities to larger, lesser known communities of potential collaborators. Universal Description, Discovery, and Integration (UDDI) specification and supporting technologies support open frameworks for businesses to store, advertise and retrieve pertinent services. Many researchers investigate approaches that ubiquitously create higher-level processes by composing services discovered in and retrieved from UDDI registries. However, there are few studies that consider the impact of registry performance on future service automation. This work focuses on evaluating the performance of UDDI registries considering variability and concurrent load of publish and inquiry requests.