Microwave resonance absorption in Co-ferrite and Co-Zn binary ferrites at 3.22cm wave-length were observed at high temperature and from room temperature to -195℃, respectively. Resonance absorption in Co-ferrite could not be detected at the temperature below 40℃, because of a large anisotropic energy in Co-ferrite. Such phenomena had not been found in other ferrites, so the resonance experiment was undertaken at high temperatures ranging from 40° to Curie point. In Co-Zn binary ferrites, the absorption disappeared below the temperature of -90℃ and -140℃ in 4CoOZnO5Fe_2O_3 and 3CoO2ZnO5Fe_2O_3, respectively, but the absorption in CoO4ZnO5Fe_2O_3 could be observed down to -186℃. The resonance fields corresponding to the maximum absorption were observed as a function of the temperature. In the case of Co-ferrite, the resonance field corresponding to the maximum absorption gradually decreased with increasing temperature up to ca. 250℃ and then rapidly increased to the Curie point. On the other hand, the absorption amount at first increased linearly with increasing temperature, afterwards passed through a maximum and then decreased rapidly up to the Curie point. The half line widths and g-factor were also obtained as functions of temperature up to the Curie point ; the half line width monotonously decreased with increase of temperature up to the Curie temperature, at which the absorption disappeared. The g-factor increased with the rise of temperature, afterwards passed through broad maximum and then decreased rapidly to the Curie point ; the value of the reonance field just about at the Curie point was found to be within 3300±100 Oe, for which g-factor was determined to be 2.02±0.06 by using the paramagnetic resonance condition
