A set of monitor foils composed of Ti. Fe, Ni, Co, Au, and Nb was irradiated for three months at the LAMPF beam stop with a neutron fluence of approximately 2 . 10¹⁹ cm^-2. The activities of a representative selection of these foils were determined in an inter-laboratory comparison. The participating laboratories (CESNEF, PTB, SCK/CEN, and EIR) used their established measuring procedures. The methods are described briefly; apparent differences in the results and possible reasons for them are discussed.