Pursuant to a congressional request, GAO reviewed the Navy's Inspector General (IG) organization's complaint resolution and Navy unit inspection activities. GAO found that: (1) Navy IG investigation and inspection practices need to be strengthened; (2) for many cases, the Navy IG did not assign an independent investigator or complete investigative documentation, did not timely or fully investigate, and failed to follow complainant confidentiality procedures; (3) the Department of Defense (DOD) and Congress cannot be assured that the Navy IG is properly investigating allegations of waste, mismanagement, or improper Navy personnel actions; (4) the Navy IG plans to develop a detailed investigation manual and training course for its investigators to strengthen their investigations; (5) systematic inspection weaknesses may not have been identified because the Navy IG did not inspect several major commands within the Navy's established 3-year cycle and IG of these major commands did not identify trends in inspection results; (6) although the Navy IG has addressed significant economy, efficiency, and effectiveness issues, it has not reported its findings or recommendations to Congress or DOD so that they can fulfill their oversight and policy responsibilities; (7) the DOD IG has not conducted a comprehensive oversight review of Navy IG inspection activities; and (8) an independent review of the Navy IG by an external organization could result in a more efficient use of Navy IG resources.