  In this paper we derive the Spitzer IRAC band period-luminosity (P-L)
relations for the Small Magellanic Cloud (SMC) Cepheids, by matching the
Spitzer archival SAGE-SMC data with the OGLE-III SMC Cepheids. We find that the
3.6micron and 4.5micron band P-L relations can be better described using two
P-L relations with a break period at log(P)=0.4: this is consistent with
similar results at optical wavelengths for SMC P-L relations. The 5.8micron and
8.0micron band P-L relations do not extend to sufficiently short periods to
enable a similar detection of a slope change at log(P)=0.4. The slopes of the
SMC P-L relations, for log(P)>0.4, are consistent with their LMC counterparts
that were derived from a similar dataset. They are also in agreement with those
obtained from a small sample of Galactic Cepheids with parallax measurements.
