This paper documents a survey of sensor technology for use in robotic hands. This is achieved by studying sensors used in the UTAH/MIT Hand, the Belgrade/USC hand, the Stanford/JPL hand and the Hirzinger Hand. Additionally, off-the-shelf available sensors as well as those under development in research labs are also evaluated. Different types of sensing covered in this report are position, torque, touch/contact force, proximity, vision, and temperature. Different options available for each type of sensing are also outlined. Major attention was given to the contact force sensor, as it is crucial for the grasping task.