The primary objective of this paper is to heighten the awareness of animal welfare issues among animal scientists. Emphasis is placed on issues relating to pharmacology and toxicology research with animals. Use of both laboratory animals and farm animals is addressed; major consideration is given to domestic livestock. Animal welfare issues are complex and have philosophical, ethical, legal, societal, scientific, and biological bases and implications. There is substantial diversity in public opinion and perception regarding use of animals in research, including the belief among some people that use of animals in research should be eliminated altogether. Increasingly, public opinion is tending toward expectations of alternatives to the use of live animals for research. From an animal scientist's viewpoint, although the availability and development of viable alternatives are increasing, live animal research in pharmacology and toxicology currently has no acceptable alternative, in many cases because of the complex interactions involved in whole-animal (biological) systems. Compliance with federal, state, and local laws, regulations, and policies requires animal scientists to use only appropriate species for research, use the minimum number of animals needed, minimize pain and discomfort, and consider alternatives to the use of live animals. In summary, it is essential that animal scientists be advocates of animal well-being and adhere to appropriate guidelines for animal care and use when conducting research with animals.