An apparatus for estimating bio-information, includes a sensor including a cover having a transmitting area provided at a center of the cover, and non-transmitting areas provided at both edges of the cover, a light source configured to emit light onto an object that is in contact with the cover, and a detector configured to detect a first optical signal of the emitted light that is scattered or reflected from the object after passing through the transmitting area, and a second optical signal of the emitted light that is reflected from the non-transmitting areas. The apparatus further includes a processor configured to estimate bio-information, based on the detected first optical signal and the detected second optical signal.