(TMZ) - Lamar Odom has just been charged with 1 count of DUI ... TMZ has learned.

TMZ broke the story ... Lamar was arrested August 30 at 3:25 AM on the 101 Freeway after cops saw him driving too slow.  He flunked several field sobriety tests and was then cuffed and taken to jail, where he REFUSED to submit to a blood alcohol test.

The fact that he refused the blood alcohol test actually helped him ... in that normally a defendant would be charged with 2 counts of DUI - driving under the influence and driving with .08 or higher.  

Here's the bad news - By refusing to take the test ... Lamar will have his driver's license suspended for 1 year.

As TMZ first reported, law enforcement sources said they believed Lamar was under the influence of both drugs and alcohol.

If convicted ... the likely outcome would be probation and an alcohol ed course since he's a first-time offender.  These cases are almost always plea bargained.

Lamar will be arraigned on Sept. 27.

Photo Credit Getty Images