That's the claim in a letter sent to a regional census director last month by the Southern California Tribal Chairmen's Association.
The letter by chairman Robert Smith says census partnerships between the tribal and federal governments have broken down and there's a danger Indians on reservations will be undercounted. He says census representatives even failed to show up to a scheduled meeting.
Census figures help the government determine how to distribute some $400 billion a year for various federal programs.
Census spokeswoman Cynthia Endo won't comment but says officials would like to discuss the matter with tribal leaders.
San Diego County has 18 tribes with about 17,000 members.