Fractionally spaced Rake (FSRake) reception is proposed for non-coherent direct sequence ultra wideband (DS-UWB) wireless communication systems. In the FSRake reception, output signal of the pulse matched filter is sampled with a faster sampling rate than the chip rate of DS-UWB signal. Computer simulation is conducted to evaluate the performance of FSRake receiver in DS-UWB wireless system with M-ary code shift keying (MCSK-UWB) over IEEE802.15.3a multipath channel. Simulation results show that the non-coherent FSRake reception provides more than 4dB SNR gain at the 10(-5) bit error rate in comparison with the conventional non-coherent Rake reception, when the number of combining paths is six in 4-ary code shift keying UWB system over IEEE 802.15.3a CM 1.