This article described the experiences of an inservice professional development program for teachers with a focus on online synchronous discussions. Transcripts of six online synchronous discussions containing 3600 messages from an online teacher professional development course were analyzed. In addition, the researchers interviewed 10 participating teachers in order to understand their perceptions toward online synchronous discussions. According to the online discourse data, the online synchronous discussions served not only as a learning tool, but also an avenue for teachers to request and provide information, socialize and support each other. The analyses also revealed that the teachers posted more social messages in the beginning and the end of discussion, and most messages did not involve any cognitive and metacognitive skills. Moreover, the interview results showed that the information exchange during online synchronous discussion was not effective for some participating teachers. Based on the interview data, synchronous discussions appeared to hold little advantage when compared to face-to-face discussions for several participating teachers that we interviewed. The problem may be resulted from lack of self-regulated skills by the participants or from the role played by the moderator.