Several researchers have investigated the impact of evidence of prior convictions on jurors' decisionmaking. Little is known about a related issue, the impact of prior acquittal evidence introduced by the prosecution on jurors' decisions. The U.S. Supreme Court recently held (Dowling v. U.S., 1990) that the admission of prior acquittal evidence does not unfairly prejudice the defendant. In addition to examining the effects of prior- record evidence on jurors' decisions, researchers in the current study also manipulated the presence of judicial instructions on the limited use jurors can make of extrinsic-acts evidence. Study participants were 105 residents, ranging in age from 19 to 71 years old, of El Paso County, Colorado, who had been called to serve as jurors between June and August 1992. In addition, 35 undergraduate students from the University of Colorado at Colorado Springs participated in a pilot testing of the materials. A written, revised summary of the bank robbery trial from the Dowling case was mailed to each subject. There were six versions of the transcript. The type of evidence presented (prior acquittal, prior conviction, or no information about a prior record) and the presence or absence of limiting instructions were manipulated in each summary. After reading the summary, participants were given a questionnaire that asked them to indicate whether the defendant was guilty or not guilty; how confident they were regarding the verdict; the credibility, likableness, and dangerousness of the defendant; the credibility of the key witness and victim of the home break-in; the credibility of the police officer who investigated the bank robbery; and the degree to which the prior acquittal or prior conviction influenced their decision when applicable. Findings show that mock jurors were more likely to convict the defendant when they had evidence of a prior conviction than when they had evidence of a prior acquittal or no-record evidence. This effect was mediated by attributions about criminal propensity. The judge's limiting instructions were ineffective in guiding jurors' use of prior-record evidence. 3 tables and 24 references