This study examined prospective middle school mathematics teachers' problem-posing skills by investigating their ability to associate linear graphs with daily life situations. Prospective teachers were given linear graphs and asked to pose problems that could potentially be represented by the graphs. Their answers were analyzed in two stages. In the first stage, the problems were evaluated in terms of whether they represented daily life situations or not and in the second stage, the conceptual validity of the responses was examined. Prospective teachers were found to experience difficulties in selecting stories that were appropriate for the structures of the linear graphs and in accurately conveying the data in the graphs through their stories. Of the five types of errors identified in the problems posed, the failure to express linearity was the most common. In addition, statistical analyses showed that success in problem-posing declined as the complexity of the data in the graphs increased.