<p>And does it matter if the second field of interest is related to the field of the first PhD?</p>
<p>Why would you ever want to do this?</p>
<p>toenail: Google is your best friend. I copied and pasted your question “Can you apply to a PhD program if you already have a PhD?” and I found the 30 pages of answers in less than a second:</p>
<p>1) Yes
2) It varies from college to college. Some colleges will not let you enroll in their school for a second doctorate if you obtained your first Phd from that school. </p>
<p>See – that was easy!</p>
<p>My uncle has both an M.D. and a Ph.D.</p>