We have analysed the first 3 orbits of Swift-XRT data obtained from GRB 100302A (trigger 414592; Cummings, et al., GCN 10458) from 125 s to 28.8 ks after the BAT trigger. The best position of the X-ray afterglow is the UVOT enhanced XRT position given in Goad et al. (GCN 10460). The 0.3-10 keV light curve shows a multiple peak structure, with three main spikes at about T+200, T+250 and T+400s, followed by a fast decay with index 3.35+-0.3 and by a break at 1ks. Later time data are fitted by a second power law with a decay index of 0.26+-0.12. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.28 (-0.15, +0.17). The best-fitting absorption column is 1.1 (-0.20, +0.17) x 10^21 cm^-2, in excess of the Galactic value of 1.9 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. If the light curve continues to decay with a power-law decay index of 0.26, the count rate at T+24 hours will be 0.01 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.3 x 10^-13 (4.7 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00414592. This circular is an official product of the Swift-XRT team.