In this work, the dark electrical resistivity, charge carriers density and Hall mobility of Ga4Se3S single crystals have been measured and analyzed in the temperature region of 200-350 K. The data analyses have shown that this crystal exhibits an extrinsic n-type of conduction. The temperature-dependent dark electrical resistivity analysis reflected the existence of energy level as 0.31 eV. The temperature dependence of carrier density was analyzed by using the single donor-single acceptor model. The latter analysis allowed the determination of electron effective mass as 0.38m(0), hole effective mass as 0.42m(0), donor impurity energy level as 0.45 eV, acceptor-donor concentration ratio (N-a/N-d) as 0.97 and a donor-acceptor concentration difference as N-d - N-a = 1.5 x 10(11) cm(-3). The Hall mobility of Ga4Se3S is found to increase with decreasing temperature following a power law of slope of similar to(-6.3). The abnormal behavior of mobility was attributed to the domination of phonon scattering and/or crystals anisotropy. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.