4:01 PM PT -- We did some more digging and discovered Rodman owes an additional $278,543 in unpaid income tax to the great State of California ... bringing his total debt to $453,027.99.
The U.S. government has a serious bone to pick with Dennis Rodman ... and not just because he's gallivanting around North Korea -- he still owes more than $174k in unpaid taxes, TMZ Sports has learned.
Official government records, obtained by TMZ Sports, show The Worm is still in serious debt ... owing $174,484.99 in unpaid state and federal taxes.
The docs show Worm owes:
-- $165,818 in federal taxes
-- $8,666.99 to the State of Michigan
The tax issues date all the way back to 2007 ... it's unclear why Rodman hasn't paid back his debt.
We tried calling both Dennis and his rep for comment -- but they're both in North Korea with Kim Jong Un.