The most frequently used mediator techniques in complex negotiations, suggestion of agreement points and reward of concessions, have received some investigation. To further assess the effects of these two techniques, 80 college students participated in simulated union management negotiations. Students were randomly assigned to represent union or management in four negotiations including suggestions of agreement points to the negotiator, suggestions of agreement points to the opponent, and mediator rewards to the negotiator's concessions. After the fourth negotiation, students completed brief questionnaires. Data analyses showed main effects upon the final offer, the total profits, and the number of agreements for the suggestion to the negotiator and the opponent. Mediators' rewards to the negotiator did not affect total concessions, number of agreements, or joint profits. Suggestions applied to the negotiator and the opponent interacted in an interfering rather than in a complementary manner. Whether or not the simultaneous application of mediator techniques to the negotiator and opponent interacts in a facilitative or interfering way depends upon which techniques produce indirect effects on the opposite negotiator. Facilitative and interfering effects frequently are likely to cancel each other. (JAC)