Ultra wideband (UWB) technology has obtained lots of attention as a strong candidate for short range indoor wireless communication because of low power consumption, low cost implementation and the robustness against multipath fading. It uses trains of short pulses which widely spread the signal energy in frequency domain. Since such large bandwidth can cause interference with other narrow band communication systems, the federal communications commission (FCC) has restricted not only the frequency region from 3.1GHz to 10.6GHz but also the transmission power level for commercial use of UWB systems. The effects of timing jitter on time hopping binary phase shift keying (TH-BPSK) UWB systems applying the FCC-constraint pulses are investigated under flat Nakagami-mfading channel and additive white Gaussian noise (AWGN). The numerical results show that two FCC-constraint pulses, PSP and MMNHP, have almost same sensitivity to the timing jitter even though they have different transceiver complexity. Additionally, the additional required power due to the timing jitter exponentially increases, but that due to the amplitude fading is not exceeded over 4dB.