The hydrogen absorption rate has been investigated by the gas-solid reaction method in the disordered and ordered (L1(2)) Pd3Mn compound. With the disordered material the measurements were carried out from 825 K up to 1038 K, with the ordered one from 485 K to 666 K. The H absorption data, analyzed according to the second Fick's equation, provided the H chemical diffusion coefficient D-c which exhibited an exponential temperature dependence. In the disordered state D-c was higher than in the ordered one in agreement with previous lower temperature data from Gorsky relaxation. This finding could be accounted for in terms of the different kinds of jumps between adjacent interstitial (1) octahedral sites that H is able to make in the two different states of order. In the disordered state H diffusion takes place through sequences of I-6-I-6, I-6 <-> I-5 and I-5-I-5 jumps (sub-index indicates the number of Pd atoms in the first atomic shell of an octahedral interstitial site), while in the state of order L1(2) the involved jumps are I-6 <-> I-4 and I-4-I-4. (c) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.