Regular graduate students registered for other classes may audit one class and associated lab, if applicable. Audit credits apply to the semester course requirements, but are not applicable to your graduate degree. If you are a student who is on support (teaching assistantship, research assistantship or fellowship) you should consider the use of audits carefully. Here is the rationale.
All students on support, must complete 12 credits each (Fall/Spring) semester. The problem is that while you may drop a course up to the tenth week of the semester, you may not add a course after the close of registration, which comes much earlier at the end of the second week of the semester. This creates something of a Catch-22. If you don't withdraw from a course in which you anticipate a bad grade, you may be placed on academic probation for poor grades, but if you drop the course, your contract will be cancelled immediately. Clearly one approach to avoiding this dilemma is to always do well in your classes, but life doesn't always work like that.
Our recommendation is to use the "Audit" as a safety valve. If you are on support, do not begin the semester auditing any course unless you are certain that you will not find yourself in trouble in any of your other courses. If it develops later that you are doing poorly in a particular course, you may change status in that course (up to 3 credits) to "Audit" as late as the ninth week of the semester and meet a lesser performance expectation for the course. You must, of course, do well enough in the audited course so that you earn an SA (satisfactory audit) for the semester. You stand a much better chance of surviving the semester AND keeping your support.