In this paper, a new antenna for wideband capsule endoscope systems is introduced. The antenna that is supposed to operate in human body has fat arm spiral structure to achieve small size and wideband characteristics. Since capsule endoscope systems are designed to operate in the human body and its front end transmits internal image data to an external receiver with high resolution, a wideband and small antenna is required. Moreover, to operate in the human body, the frequency of the proposed antenna is determined from the electrical properties of body materials. The bandwidth of the proposed antenna is 460-535 MHz (75 MHz) for VSWR < 2 and it has omni-directional radiation pattern. The height of the proposed antenna is 4 mm and diameter is 10 mm. Because of wideband characteristic and small size, the proposed antenna is suitable for wideband capsule endoscope systems.