Disclosed is an organic light emitting display device, which is capable of compensating for variations in the characteristics of driving transistors, comprising a display panel including a plurality of pixels, each pixel having a driving transistor for operating a light emitting device to make the light emitting device emit light with a data current corresponding to a data voltage; a panel driver for detecting the characteristics of the driving transistors including at least one of mobility and threshold voltage of the driving transistor included in each pixel during a time period when there exists no user around the display panel, generating compensated input data by compensating input data according to the characteristics after the detection of the characteristics is completed, and generating data voltage through the use of the compensated input data; and a sensor for sensing whether or not there exists a user around the display panel, and supplying the sensing result to the panel driver.