To detect players who are engaged in real-money trading (RMT) in massively multi-player online role-playing games (MMORPGs), behavior of players was analyzed using log data of a commercial MMORPG. A closed test evaluated the effectiveness of several player-wise statistics derived from the log data in detecting RMT players. Categories and Subject Descriptors J.4 [Social and Behavioral Sciences]: Economics; K.4.2 [Computers and Society]: Social Issues; I.5.2 [Pattern Recognition]: Design Methodology General Terms Experimentation, Management Keywords RMT, MMORPG, online game, log data