Prepared by the District of Columbia Street Law Project for its 22nd annual city-wide mock trial competition, this instructional handout provides the material for a mock civil trial in which Sandra Williams sues Gregg Mason for negligent transmission of the Human Immuno-Deficient Virus (HIV). On the night of May 15, 1990, Sandra and Gregg engaged in unprotected sexual intercourse. Earlier that day, Gregg had taken an HIV blood test that was later to reveal that he was HIV-positive. After Gregg informed Sandra of the results, she was herself tested and diagnosed as HIV-positive. Sandra claims that Gregg negligently transmitted the disease and sues him for medical costs, loss wages, and emotional suffering. The handout clarifies the laws and explains the legal precedents. As evidence, the handout provides a summary of estimated medical costs for individuals infected with HIV; the questionnaire Gregg completed in the health clinic on May 15; and witness statements from Sandra, Sandra's college roommate, her personal physician, Gregg, the bartender from the bar where Sandra and Gregg met, and an Acquired Immune Deficiency Syndrome (AIDS) specialist. Through participation in mock trials and analysis of the activity, students gain an insider's perspective on courtroom procedure and a basic understanding of the legal mechanism through which society resolves its disputes. Mock trials develop critical analysis, questioning and listening skills, and skills in preparing and organizing materials. (JD)