A two-stage difference-based estimation method is presented to extract the timing skew of each sub-ADC in time interleaved analog to digital converters (TIADCs). Compared with the previous techniques, such as the correlation-based method, the main advantage is that it greatly reduces the number of multipliers and does not require digital filters. Simulation results of a four-channel TI-ADC behavioral model and experimental results from a commercial 12-bit 3.6-GS/s TI- ADC demonstrate the effectiveness and superiority of the proposed estimation method.