Participant support costs are those costs paid to (or on behalf of) participants in meetings, conferences, symposia, training activities, workshops and similar events.

Specifically, participant support costs may include costs of transportation or travel allowance, per diem, manuals and supplies (only those directly attributable to individual participants), tuition and stipends, publication and other related costs for participants or trainees. The number of participants to be supported must be entered in the proposal budget. These costs also must be justified in the budget justification section of the proposal. Some programs, such as Research Experiences for Undergraduates, have special instructions for treatment of participant support.

Participant support costs are excluded from the calculation of Modified Total Direct Costs (MTDC).

Participant support costs should not be confused with general travel costs which may be incurred by principal investigators and others as those costs relate to individual research and other projects.