Provided are an ultrasonic diagnostic apparatus and a method of operating the same. The ultrasonic diagnostic apparatus includes: a first ultrasonic transceiver that transmits an ultrasonic signal and receives a first echo signal that is reflected, through a deactivated probe from among a plurality of probes; a gel detector that determines whether gel is applied on the deactivated probe based on the received first echo signal; and a controller that activates the deactivated probe when it is determined that the gel is applied on the deactivated probe.