Provided are an information processing system, an information processing method, and a program capable of favorably estimating the association between persons appearing in pictures. This information processing system includes: a correspondence relationship estimation unit for determining a scale indicating a possibility that one or more persons appearing in pictures captured respectively at a first time by a plurality of video cameras, and one or more persons appearing in pictures captured respectively at a second time, which is later than the first time, by the plurality of video cameras, are respectively associated with each other, and estimating a correspondence relationship between the person appearing at the first time and the person appearing at the second time in consideration of all scales relating to at least one person appearing at one of the first time and the second time, and all persons appearing at the other time; and a person-to-be-tracked registration unit for receiving an input of correspondence information to the effect that at least a part of one or more persons captured at the first time corresponds, or does not correspond, with at least a part of one or more persons captured at the second time.