Partnerships are essential for the success of conservation organizations as they strive to achieve the ultimate goal of restoring and preserving biodiversity. Now is a particularly crucial time to develop partnerships owing to increasing financial constraints on all organizations and the urgent need for species recovery and habitat preservation. This study identified characteristics of successful conservation partnerships between Association of Zoos and Aquariums (AZA) accredited institutions and related facilities, US and international governmental agencies, and nongovernmental organizations. One hundred and five AZA accredited zoos and aquariums or related facilities participated in the preliminary survey. Staff at 75 of those zoos and aquariums were interviewed by telephone for a follow-up survey. Respondents were asked which characteristics most contributed to the success of their past and current conservation partnerships. Data were analyzed in two ways: descriptive statistics and principal component analysis. Descriptive statistics showed that effective leadership, clear and consistent communication, and trust between partners were the top three characteristics that led to partnership success. Ineffective leadership by those in charge, lack of clear, consistent communication between partners, and unreliable or insufficient sources of funding were the top three characteristics that inhibited partnership success. Using principal component analysis, the variables for each question on the questionnaire were reduced to a smaller subset of categories. Structure, personalities, process, and commitment were the four principal components of successful conservation partnerships. The three principal components that inhibited conservation partnerships were: communication, partnership personnel, and partner inequality. Results gained from this research are sure to increase the probability of success both for conservation partnerships that have already been established and for those that may develop in the future. Zoo Biol 26:471-486, 2007. (c) 2007 Wiley-Liss, Inc.