The results of measurements leading to the elaboration of a reliable and accurate dose rate determination for a cobalt irradiator „Issledovatel” were presented. The dose measurements were done by means of the classic Fricke dosimeter. The conclusions from measurements can be useful also for the dosimetry of other kinds of cobalt irradiators. The measurements were performed by a newly employed Laboratory for Measurements of Technological Doses staff and were a practical test of their proficiency in gamma ray dosimetry.