CBOT December soft red winter wheat settled down 8 cents at $4.20 a bushel.
K.C. December hard red winter wheat ended down 10-1/4 cents at $4.17-3/4 a bushel and MGEX December spring wheat fell 4-1/4 cents to $6.24-3/4.
Several deferred months in the CBOT and K.C. markets fell to contract lows.
Futures were anchored by strong competition for export business, following a record-large harvest in Russia.
Ahead of the US Department of Agriculture's weekly export sales report on Thursday, analysts surveyed by Reuters expected the government to report US wheat sales at 350,000 to 550,000 tonnes.
Egypt's agriculture ministry said it was awaiting a Cabinet ruling after a court reinstated a ban on wheat imports containing the common ergot fungus, renewing uncertainty over a policy that has disrupted trade.