NASA is developing three racks containing regenerative water recovery and oxygen generation systems (WRS and OGS) for deployment on the International Space Station (ISS). The major assemblies included in these racks are the Water Processor Assembly (WPA), Urine Processor Assembly (UPA), Oxygen Generation Assembly (OGA), and the Power Supply Module (PSM) supporting the OGA. The WPA and OGA were developed by Hamilton Sundstrand Space Systems International (HSSSI), Inc. while the UPA and PSM were developed by the NASA Marshall Space Flight Center (MSFC). Test and verification activities have been completed for the WRS and OGS systems and planning for launch and on-orbit activation is underway. This paper summarizes the status as of April 2006 and describes some of the technical challenges encountered and lessons learned over the past year.