The effective resonance energy E-r-values for the (n,gamma) reactions of Ga-71, As-75, Dy-164, Er-170 were determined by the cadmium ratio method using dual monitor (Mn-55-Mo-98) having favorable resonance properties. The powder samples with and without a 1 mm, thick Cd cylindrical box were irradiated in an isotropic neutron field obtained from three Am-241-Be neutron sources. The induced activities were measured with a 120.8% relative efficient p-type Ge detector. The necessary correction factors for thermal neutron self-shielding (G(th)) and resonance neutron self-shielding (G(epi)) effects were taken into account. Thus, the experimentally determined E-r-values were 174 +/- 36 eV for Ga-71, 112 +/- 23 eV for As-75, 225 +/- 47 eV for Dy-164 and 129 +/- 27 eV for Er-170, respectively. The present experimental results for the E-r-values were also theoretically calculated from the newest resonance data. Since the experimentally determined E-r-values for the Ga-71, As-75, Dy-164 and Er-170 isotopes are not available in literature, the present experimental results are compared only with the present and earlier calculated ones. It is found that there are still large discrepancies (within range of 3-15%) between the experimentally determined E-r-values and the calculated ones obtained by recent resonance data for the above isotopes. A wide variation of the available E-r-values implies the need for the new experimental determinations of E-r-values for other isotopes, especially used in k(0) standardization studies. (c) 2008 Elsevier Ltd. All rights reserved.