Influences of user's posture and contact conditions of electrodes on the transmission characteristics of human body communication (HBC) were studied. A subject wore a transmitter on the left wrist and touched the receiver electrode with his right or left index finger. User's postures were selected from possible scenarios in practical applications. Electrodes of the transmitter and/or the receiver were covered with thin insulating materials to avoid direct metallic contact with the human body. Differences caused by this insulation were also evaluated.