A bio material receiving device includes a thin film transistor (“TFT”) including a drain electrode, and a nano well accommodating a bio material. The drain electrode includes the nano well. The TFT may be a bottom gate TFT or a top gate TFT. A nano well array may include a plurality of bio material receiving devices. In a method of operating the bio material receiving device, each of the bio material receiving devices may be individually selected in the nano well array. When the bio material is accommodated in the selected bio material receiving device, a voltage is applied so that another bio material is not accommodated.