But Democratic-leaning firm Public Policy Polling (PPP) found Romney way ahead by 10, with 52 percent to Obama's 42 and a margin of error of plus or minus 4 percentage points.
According to RealClearPolitics' polling average, that still puts Romney ahead in Missouri by almost 5 percentage points, since most polls prior to Akin's comments on Sunday showed Romney ahead in the state.
The two polls are the only presidential polls conducted so far in Missouri in the week since Akin said during a local TV news interview that few women get pregnant from "legitimate rape" because "the female body has ways to try to shut that whole thing down."
Both are one-day polls, with PPP's conducted Aug. 20 and Rasmussen's on Wednesday. The Akin controversy has largely dictated the headlines throughout this week, meaning voters in Missouri might still be in the process of deciding whether it influences their vote.
Another Rasmussen poll conducted on Wednesday was under fire from Democrats. The poll showed Sen. Claire McCaskill (D-Mo.) leading Akin by double-digits, leading Democrats to claim the GOP-leaning firm is a "tool of the Republican establishment.
Romney has condemned Akin's remarks as "insulting, inexcusable and, frankly, wrong."
— This story was updated at 11:40 a.m.