This research examined the relationship between Linguistic Style Matching (LSM)-the degree to which negotiators coordinate their word use-and negotiation outcome. Nine hostage negotiations were divided into 6 time stages and the dialogue of police negotiators and hostage takers analyzed across 18 linguistic categories. Correlational analyses showed that successful negotiations were associated with higher aggregate levels of Linguistic Style Matching (LSM) than unsuccessful negotiations. This result was due to dramatic fluctuations of LSM during unsuccessful negotiations, with negotiators unable to maintain the constant levels of rapport and coordination that occurred in successful negotiations. A further analysis of LSM at the local turn-by-turn level revealed complex but organized variations in behavior across outcome. In comparison to unsuccessful negotiations, the dialogue of successful negotiations involved greater coordination of turn taking, reciprocation of positive affect, a focus on the present rather than the past, and a focus on alternatives rather than on competition.