The objectives of the workshop were to (1) summarize the state of the art in sublethal biological effects studies, (2) determine the relationships or interactions between organismal- and cellular- and molecular-level studies, (3) discuss the strengths and weaknesses of current studies, and (4) define new or needed research directions. Four major topics were considered: (1) sublethal effects of stress at the organismal level; (2) measuring response to sublethal stress at the organismal level; (3) sublethal effects of stress at the cellular and molecular level; and (4) measuring sublethal response to stress at the cellular and molecular level. Introductory statements, subcommittee reports, keynote address, and abstracts of presentation are presented.