A temperature sensor includes a band gap reference (BGR) circuit, a voltage generation unit and a digital CDS circuit. The band gap reference (BGR) circuit generates a reference voltage proportional to a temperature. The voltage generation unit generates a first voltage and a second voltage based on the reference voltage, where the first voltage and the second voltage are proportional to the temperature. The digital CDS circuit generates a digital signal corresponding to the temperature by performing a digital correlated double sampling (CDS) operation on the first voltage and the second voltage. The temperature sensor is able to detect a temperature accurately.