Switching Fields from Undergrad to Grad?

Recently I received the following question:
"Is it common for students to pursue an undergraduate degree in one field and then a graduate degree in another? My undergraduate degree is History but I want to pursue a master's degree in Political Science. Is it necessary to have a BA in Political Science in order to pursue the MA?"

Many students seek graduate degrees in areas outside of their bachelor's degrees. The key is to demonstrate that you have the requisite experiences and match the program. So, if your BA is in Math, for example, and you wish to apply to a master's program in Biology, it would be a good idea to take some science courses to demonstrate that you have a basic science background as well as the capacity to succeed in science.

In this particular case, an undergraduate degree in History is a basic liberal arts degree that can serve as good preparation for a master's degree in Political Science if the applicant can demonstrate a good fit to the program. Graduate programs want to see evidence that a student is interested in a particular field, has a rudimentary knowledge base, and shows promise in fulfilling degree requirements. They want to know that you can get through their program.

In your application draw attention to any courses you've taken or experiences that illustrate your interest or competence in the area to which you aspire. Explain why you're making this step -- this transition from one field to another -- why you have the background to do so, and why you make a good graduate student.

Also see:
Should I Apply to Graduate School at the Same University Where I Earned My BA?
Will your prior graduate degree be held against you in admissions?
Graduate School: Questions & Answers