In this study, the authors propose a new pulse waveform design methodology for ultra-wideband (UWB) applications, namely spectrum shifted Gaussian waveform (SSGW) approach. Specifically, UWB pulses can be generated by superposition of Gaussian sub-carriers, which can be used to fit Federal Communication Commission (FCC) spectrum masks specified for UWB applications. In this way, it can match with the FCC masks much better than those generated using the traditional methods based on Gaussian or Hermite pulses and their higher order derivatives. The SSGW works with a low computational complexity and offers a unique agility in design of time-domain pulse shapes to fit different power spectrum density masks. In principle, the SSGW approach can also be used for pulse waveform design in many other bandwidth efficient communication systems, not necessarily limited only to UWB systems.