The theory of evolution has beenused in arguments regarding animalexperimentation. Two such arguments areanalyzed, one against and one in favor. Eachargument stresses the relevance of the theoryof evolution to normative ethics but attemptsexplicitly to avoid the so-called naturalisticfallacy.According to the argument against animalexperimentation, the theory of evolution`undermines' the idea of a special humandignity and supports `moral individualism'. Thelatter view implies that if it is wrong to usehumans in experiments, then it is also wrong touse animals, unless there are relevantdifferences between them that justify adifference in treatment. No such differencescan be found with regard to animals which lead`biographical lives'.The argument in favor of animal experimentationis based on evolutionary psychology. It statesthat humans, as all social animals, arespeciesist by nature and stresses that thisshould be taken seriously in normative ethics.This does not mean that animal interests shouldnot be considered, only that vital humaninterests may outweigh them.In order to assess the arguments, one has totake a stand on certain more basic issues: `is'versus `ought', impartiality versus specialobligations, and feelings/intuitions versusreason. Given the author's own position withregard to these more basic considerations, theevolutionary argument in favor of animalexperimentation is judged to be more convincingthan the one against but not decisive. It isalso maintained that not all animal experimentsare acceptable. Which animal experiments areacceptable and which are not has to be decidedon a case-by-case basis.