In this paper we propose to model a negotiator’s decision-making behavior, expressed as preferences between an offer/counter-offer gamble and a certain offer, by learning from implicit choices that can be inferred from observed negotiation actions. The agent’s actions in a negotiation sequence provide information about his preferences and risk-taking behavior. We show how offers and counter-offers in negotiation can be transformed into gamble questions providing a basis for inferring implicit preferences. Finally, we present the results of experiments and evaluation we have undertaken.