Registration info, test dates, and fees for the ISEE are always changing, so be sure to check out the ISEE homepage. Here, you can find the latest information about registering for the ISEE, and you can even register online.
The online registration allows you to locate and register for an open test site during various times throughout the year. However, some schools have closed registrations where they test their existing students or students who are applying to the school. Always check with the school you're applying to for more information about registering for the ISEE because closed registrations must be handled by the specific school. Start by contacting the school's admission officer, and go from there. After you register for a test, you can reschedule the test if necessary or access additional information about inclement weather, testing accommodations, and so forth.
When you take the ISEE, bring your ISEE admission ticket, some form of identification, two sharpened #2 pencils, a good eraser, and a pen for the writing sample. (Note: Make sure the pencils are #2, which is usually labeled on the box and the pencil itself, because other kinds may not be read correctly by the scoring machine.) You can't bring books, papers, calculators, phones, watches with alarms, or basically any other electronic devices. Also, no visitors are allowed.