Abstract: The problem of transient response of a spiral fin, with its end insulated, is analyzed with the base end subjected to a variation of fluid temperature. The method of Laplace transforms and with a technique derived by the Keller and Keller, of which has an exponential like form, is applied to study the transient response. Both of a unit step change and a sinusoidal temperature change are analyzed. Moreover, the results of the temperature distribution and the heat flux at the base of the fin are obtained. Solutions are developed for both small and large values of time. Typical results are presented in both tables and graphs. Comparisons are made and the results show a good agreement in the physical circumstance.