In the 2020 Cook County, State's Attorney election held on November 3, 2020, incumbent state's attorney Kim Foxx (a Democrat) won reelection to a second term, defeating Republican Pat O'Brien in the general election. Foxx had earlier defeated three opponents in the Democratic primary.
Incumbent Kim Foxx faced three opponents in the two former Assistant State's Attorneys, Bill Conway and Donna More, and former Chicago alderman Bob Fioretti.
The money spent in the Democratic primary made this the most expensive State's Attorney election in Cook County to date. Conway raised $11.9 million in campaign funds, most of which was from his father William E. Conway's cumulative donations of $10.5 million. Foxx raised $2.8 million, and her biggest donors include Fred Eychaner and the political action committee of SEIU Illinois. More raised $406,000 and Fioretti raised $20,000.
The following candidates ran for the Democratic Party nomination for State's Attorney:
Pat O'Brien defeated Christopher Pfannkuche. Pfannkuche had been the Republican nominee for State's Attorney in 2016.
The following candidates ran for the Republican party nomination for State's Attorney:
Kim Fox's performance 54.21% vote share was the lowest performance by a Democratic nominee in a Cook County state's attorney election since 1996. It was also the worst that a re-nominated incumbent has performed in a general election for Cook County state's attorney since the same election, which saw Republican incumbent Jack O'Malley lose reelection. Conversely, O'Brien's 39.08% share of the vote was the best performance by a Republican since 1996 and Dennehy's 6.71% share of the vote was best performance by as third-party candidate since 1996.
Only Democrats have held this office ever since Richard A. Devine unseated Republican Jack O'Malley.