The imaging speed and quality of a Fourier-domain optical-coherence-tomography (FD-OCT) technique is largely limited by the resampling process. A time-domain interpolation approach based on zero padding is proposed that gets a close fall-off but much-reduced imaging time in FD-OCT data processing as compared with the common zero-padding interpolation method. The experimental results obtained with an FD-OCT system using a 2048 pixel line scan camera showed that the fall-off was improved by ~2 dB in deep z position and that the processing time was reduced to 468 ms per 400 axial scan lines with a Pentium Dual E2140 computer; that is, a more than 95% reduction compared with the conventional zero-padding approach.