First and most importantly why would you want to take both exams, do yo want to be a dentist or a physician. Seriously make up your mind, do some shadowing find out which one fits you best. As far as the exams are concerned they are nothing alike. The mcat is a reading based exam, where most of the answers are found in the passages provided. On the dat the it is straight knowledge for the most part. The mcat has bio,gen chem, organic, physics, and a reading section. It also has a writing section but it is not a big deal no studying required for that. The dat has bio, orgo, gen chem, reading math, and perceptual ability. the bio on the dat is broad with ecology, evolution and plant stuff. So it really depends on your test taking style. Just to let you know if you take both and apply to both this will be looked down upon by your peers and interviewers. This is something that is also asked on the application when you apply to medical or dental school. Oh by the way why the heck would you want to take both exams, their expensive, time consuming and stressfull.