the arteries. The blood pressure of a human varies continuously due to physical activity,medication,anxiety,and emotions.The body has unique mechanisms to regulate a person’s blood flow; whenever a person’s blood pressure drops, the heart rate increases to pump more blood and the arterial walls contract to increase the blood pressure. Blood pressure is typically measured using a mercury sphygmomanometer. However, to check a person’s blood pressure duringunexpectedsituations,thereisaneedforaportable,con- venient device or apparatus. Despite the availability of digital wrist and arm blood-pressure meters, most people do not carry these devices during their daily commute to the work place, gymnasiums, recreational facilities, etc. The only device which is omnipresent with people in all walks of their life is the mo- bile or smart phone. The mass production of smart phones with built-in sensors such as an accelerometer, a camera with flash, andamicrophonesensorhasmotivatedustotaptheirbenefitsto the biomedical domain. Although Scully et al. [1] developed a methodology for estimating the vital signs using a smart phone it does not include the blood pressure estimation.