Four experiments are presented which explore the effects of warning layout (spatial structure) and organization (semantic structure) on the ability to recall and the tendency to read warning information. Warnings were either presented in paragraph layout or in a meaningfully indented "outline layout." Warning information was organized by hazard, type of warning statement, or randomly. Experiment 1 results indicate that layout and organization reliably influenced perceptions of warning eye appeal, ease of processing, and effectiveness. However, a test of recall in Experiment 2 did not reflect the effects of these variables. In Experiments 3 and 4 warnings were presented to subjects in an incidental warning paradigm. The results of these experiments indicate that warnings in outline layout elicited less variability in reading rates, were more likely to be read, and were more likely to elicit warning compliance. Implications for warning design and future research are discussed.