The specific absorption rate (SAR) on a human head due to the radiation of mobile phones can be influenced by many parameters, including the phones' antenna design and profile. In this paper, an experimental study of the characteristics of the SAR of mobile phones is presented. Statistical results illustrate that mobile phones, in general, satisfy the ICNIRP safety limit, and that the SAR values are affected by the transmission frequency of mobile phones. In most cases, the maximum SAR is at the cheek position and is twice that at the ear position. We conclude that there is no significant difference in the SAR value between phones with internal and external antennas and that, at the ear position, the SAR value of the flip phones is about 22% lower than that of nonflip phones. We also conclude that the SAR hot spot is generally located near the antenna position.