The effect of nano-sized cobalt-aluminate pigment on thermal behavior of a typical frit was investigated. The nano-sized cobalt-aluminate powder was prepared by combustion method and the synthesized powder was calcined at 800 and 1000 degrees C. The prepared powder was characterized by DTA-TG, BET. SEM and TEM techniques. 2.0 wt.% of the calcined powders were added into the used frit and hot stage microscopy, HSM, tests were carried out on frit and modified glazes to understand the role of calcination temperature on melting behavior. The differences found in HSM data were evaluated by Vogel-Fulcher-Tamman equation for the estimation of viscosity. The results showed that viscosity increases with addition of pigment. It was found that the surface tension of frit and the glaze prepared with addition of pigment calcined at 1000 degrees C were not high enough to form spherical shape but, the calcined powder at 800 degrees C causes the highest surface tension. (C) 2011 Elsevier B.V. All rights reserved.