Democratic Party officials blamed technical problems for chaos in the counting of what was meant to be the official launch of the primary season to pick a candidate in the November presidential election.
"Nothing works, just like they ran the country," President Trump said in a tweet, however.
President Trump won his own Republican caucuses in the Midwestern farm state on Monday night with little effort, as expected, given that it was effectively never a contest.
He said "the only person that can claim a very big victory in Iowa last night is 'Trump.'"
President Trump's son Eric tweeted that Republican voting "broke ALL-TIME records for turnout for an incumbent president! The energy here in #Iowa is electric!"
With Democrats increasingly questioning the role of Iowa and its arcane caucusing system as the first and highly influential chapter in their primary season each election, the President again needled his opponents.
"It is not the fault of Iowa, it is the Do Nothing Democrats fault. As long as I am President, Iowa will stay where it is. Important tradition!" he tweeted.
Iowa Democratic officials say faulty technology has held up the results of the caucuses and that extra time is needed to ensure accurate results are reported.
However, Republicans led by President Trump have for days been suggesting that the Democratic Party is conspiring to deny victory to the farthest left candidate Bernie Sanders, while promoting centrist Joe Biden.
President Trump paints Senator Sanders as a "radical socialist" and says he'd love to face him in the election.
The President's campaign manager Brad Parscale told The Washington Post: "It would be natural for people to doubt the fairness of the process."
Senator Lindsey Graham referred to an opinion poll that was cancelled on the eve of the caucuses because organisers said there had been procedural glitches and pushed the idea that a conspiracy was underway.
"What are the odds that: most anticipated poll of the year ( @DMRegister ) is cancelled. voting system completely crashes. ....and it has nothing to do with a Bernie blowout and a Biden crash?"
