We investigated the discharge characteristics in a cold cathode lamp of 4 mm inner diameter used for backlighting liquid crystal displays. The electrode on one side of the lamp was made of nickel, and that on other side was platinum. The Ne gas pressure filling the lamp was 53 hPa. The cathode voltages of a lamp with the electrodes made of different materials were simultaneously measured with a high voltage probe connected to a digital oscilloscope when the lamp was operated by a sine wave power supply under the same discharge condition. The breakdown and maintained voltages in the case of the nickel electrode were lower than those of the platinum electrode. The measured reignition voltages were almost constant breakdown voltages in the frequency region of 0.1 to 100 Hz. In frequencies above 100 Hz, the reignition voltages decreased sharply, a becoming close to the maintained voltages. The accurate breakdown voltage was estimated to be less than a 100 Hz sine wave.