Troy Price, chairman of the Democratic Party in Iowa. has resigned after last week's caucus was beset with technical issues, questions over accuracy and delays, a media report said on Thursday.
"While it is my desire to stay in this role and see this process through to completion, I do believe it is time for the Iowa Democratic Party to begin looking forward," the BBC quoted Price as saying in his resignation letter on Wednesday.
"My presence in my current role makes that more difficult."
He then added that the Iowa Democrats were "not the only party to blame", and mentioned the partners and vendors who were also involved.
In the letter, Price said that "the precinct and satellite caucus meetings themselves went well", but conceded that the process of reporting results was "unacceptable".
In the February 3 caucus, the Iowa Democratic Party distributed a new app, called Shadow, to precinct officials that was supposed to help them report results more quickly.
Due to an issue with the app, which the party said was a coding error, there was a delay in results, leading to ultimate chaos, the BBC reported.
In the end, the results were finally released three days later than expected.
Former Mayor of South Bend, Indiana Pete Buttigieg won with a narrow 0.1 per cent victory over veteran Vermont Senator Bernie Sanders in terms of delegates, while the latter won the popular vote.
Since then, the Sanders campaign has asked for a "recanvassing" check of the vote.
Iowa Democratic leaders will elect a new local leader on Saturday.
In US elections, the Iowa caucus is the important first step in choosing the challenger to the incumbent president.
Primaries and caucuses are a string of nationwide state-by-state votes, which culminate in the Democratic nominee being chosen at the party convention in July.