The dielectric properties of an organic light emitting diode have been studied. Dielectric constant showed the frequency independence in the low frequency range below 100 kHz, while the frequency dependent property was observed at above 100 kHz. Dielectric loss factor showed the peak at about 300 kHz, which might be attributed to the dipolar polarization. The dielectric relaxation time is calculated to be about 0.531 mus from the complex dielectric constant plot. We obtained the frequency dependent properties of OLED by measuring its capacitance and quality factors.