Police in Chiang Mai swooped after investigations into a counterfeit currency ring.
Arrested by the side of Suthep Road was 45 year old Somporn or Phra Somporn, a monk attached to a well-known temple in Mae Teng.
He had 194 $US 100 bills and thousands more in Myanmar kyat in his satchel.
The US consulate in Chiang Mai confirmed the dollars were all fakes.
It appears that the monk bought them cheap in Mai Sai before exchanging them at booths and shops all over the northern Thai city.
Somporn will now be defrocked then charged, reported Channel 7.