Terrell Owens -- MASSIVE Break in Child Support Cases

Terrell Owens just scored the biggest deal of his career since he signed with the 49ers -- successfully lowering his exorbitantly expensive monthly child support payments to FOUR different baby mamas.

Sources close to T.O. tell TMZ, the former NFL star was able to convince the judges in each of his child support cases to "drastically decrease the amount he was paying."

T.O. had originally been ordered to pay between $5,000 and $20,000 per child per month -- and with no new football contract, he was seriously struggling to make ends meet.

But now, we're told the new payment plans -- the details of which are sealed -- are way more affordable ... and "accurately reflect the amount of money [Terrell] is making."

It gets even better -- we're told T.O. was also able to establish visitation in some cases, something he had never asked for before.