Study data were obtained through the use of written questionnaires submitted to 143 jurors and oral interviews with 24 subjects in Philadelphia. Variables considered include demographic information on jurors, personal characteristics of trial participants, influence of trial publicity on jurors, juror satisfaction with the verdict, and dynamics of the deliberation process. According to results, the presentation of the facts by the defense attorney is the factor that most strongly influences jurors. Other variables, in order of influence, are presentation of facts by the witnesses, by the prosecuting attorney, by the judge, and by the defendant. The presentation of facts by the plaintiff is the least-mentioned variable. A relationship is evident between the type of trial and the personal characteristics of trial participants which influence jurors. In civil trials, jurors are influenced by the defense attorney's manner of speaking while in criminal cases, jurors give greater weight to the presentation of facts. Authoritarian jurors are less likely than nonauthoritarian jurors to be influenced by the prosecuting attorney's lifestyle, the witnesses' education, the defense attorney's speaking manner and presentation of the facts, the prosecuting attorney's personality, and witnesses' appearances. Jurors over 51 and under 30 years old are less likely to be influenced by witnesses' education than jurors in the middle-age group. Jurors interviewed orally complain about the unclear presentation of facts and confusions not straightened out by judges during the trial. Legal education of citizens is recommended to reduce confusion about trial procedures.