This thesis examines the impact that third-party identity and techniques have on mediation outcome. The roles of the OAS and the Carter Center in the negotiations between the Venezuelan government and the opposition (DC), during the period 2002-2003, and the implementation of the agreement in 2004 are compared as representing track I and track II actors and styles. Using a process-tracing methodology, five conflict mappings and stages of conflict are combined with the results of focused interviews to main participants of the negotiation process. The analysis shows a significant impact of third-party identity and strategies on the outcome of mediation. Moreover, the outcome is more likely to be successful when track II actors, actually track I ½, participate as mediators in the actual negotiations. The most effective strategies used by third parties, dependent on the timing of the intervention and the stage of conflict, are communication and formulation strategies.