The maximum total compensation allowed by NIH for the support of a graduate student employed on a research grant or a cooperative agreement is tied to the zero level National Research Service Award (NRSA) stipend in effect at the time the grant award is issued.  The current 2009 level is $37,368.

Total compensation includes salary, fringe benefits, and tuition remission, and represents compensation for "full-time" graduate student work, which is the maximum the University will allow students to work outside their studies.  For UND graduate students, "full-time" means 50% (4.5 person months) during the academic year and 50-100% (1.5-3 person months) during the summer months, depending on the graduate program.  For students working less than "full-time", the NRSA zero level ceiling should be prorated.

If the total compensation for the support of a graduate student exceeds this limitation, the NIH may allow you to rebudget project funds in order to charge more than the limitation amount for the actual cost of a graduate student. The NIH allows its project funds to be used to compensate a graduate student up to the "amount paid to a first-year postdoctoral scientist at the same institution performing comparable work." 

See the NIH Notice (http://grants1.nih.gov/grants/guide/notice-files/NOT-OD-02-017.html) and the current NRSA Stipend Levels (http://grants.nih.gov/training/nrsa.htm) for more detailed information.