Most trial attorneys believe that repeated jury service produces several effects in jurors, one of the most important being an increased disposition to convict criminal defendants. Case law, however, shows that the courts have been reluctant to rule that jury service introduces an implied bias against defendants. In the sample of 175 cases, all were felonies except for 20 that came up on appeal from the lower court. In this jurisdiction, a juror typically is on call for one month and then not recalled to jury duty for some time, usually much longer than one year. Analysis of these court records revealed that with larger numbers of experienced jurors on a jury, the jury is more likely to convict. The total amount of experience represented on the jury was also positively and significantly related to jury conviction proneness. The selection of a foreperson was significantly predicted by experience, whether as a juror or previous foreperson, and by sex, with males more often picked. Foreperson experience and sex did not predict jury verdicts. There was no evidence that jurors who convict on their first trial are retained more frequently for subsequent service. A surprising finding was that jurors who initially hang have a lower frequency of subsequent service that either those who acquit or those who convict. Tables, graphs, and 17 references are supplied.