Temperature effect on the critical micelle concentration of hexadecyl trimetyl ammonium bromide over the range of $2^{circ}-50^{circ}C$ has been investigated by the method of electrical conductivity. The values obtained have been formulated as a power series in T. Several thermodynamic parameters have been calculated for the temparature range examined and their values have been discussed in the light of current theories on the participation of solvent in micelle formation.