Reliability of transistors is important to a-Si:H TFTs for integrated gate drivers. Because the life time of a-Si:H TFTs indicates the life time of LCD which adopts a-Si:H TFTs for integrated gate drivers on panel. With bias temperature stress, we could estimate the reliability of a-Si:H TFTs. Threshold voltage shift and decrease of on-current occurred by applying bias temperature stress. In this study, we investigated the effect of heat-treatment on reliability of a-Si:H TFTs for integrated gate drivers. With heat-treatment, the reliability of a-Si:H TFTs was improved and output signal of integrated gate dirivers was fine. This can be explained by that heat-treatment makes number of defect sites in channel reduce and cures the interface of active and gate insulator.