Biology teachers are accustomed to engaging individuals who do not accept biological evolution. Denial of evolution ranges from ignorance of the evidence to outright denial or distortion of data. The list of science denial topics has grown alarmingly over the years to include: HIV as the cause of AIDS, exaggeration of the health and environmental risks of genetically modified organisms, existence of holes in the ozone layer, the rise in antibiotic resistance, health risks caused by cigarette smoking, exaggeration and denial of harmful side effects of pesticides, water and environmental damage caused by hydraulic fracturing, the fear that vaccines do more harm than good, and, of course, global warming and climate change. Teaching climate science has become so perilous in some school districts that the National Center for Science Education, long known for activism in the arena of evolution education, has greatly expanded efforts in the arena of climate. In the face of denial by a substantial portion of society, the natural tendency of a scientist or educator is to pile on the data and examples, deepen explanations, and reason rigorously. However, such strategies may not be the most effective and are certainly not sufficient. In this article, the author will explore the nature and roots of science denial and review resources that instructors and students can use to recognize denial strategies while deepening their understanding of the scientific process. (Contains 4 figures.)