The interlayer coupling in Co/Pt multilayers has been investigated via the measurements of extraordinary Hall effect. In the conventional [Co/Pt](n), multilayer, the coercivity H(c) has been observed to increase exponentially for n<6 and almost linearly for n>6 with the decrease of temperature. Surprisingly, H(c) for n = 1 shows the fastest increase at low temperatures, and becomes the largest one at T<40 K. As a function of the repetition number n, the almost temperature-independent oscillation of H(c) has been observed, being indicative of the Ruderman-Kittel-Kasuya-Yosida type ferromagnetic interlayer coupling in the [Co/Pt](n), multilayer. However, the antiferromagnetic interlayer coupling can be realized via the spin-valve configuration of the Co/Pt multilayer. In the Co/Pti[Co/Pt](n), multilayer, the antiferromagnetic-to-ferromagnetic transition of the interlayer coupling has been observed at low temperatures. These observed phenomena are strongly related to the temperature-dependent polarization in the Co/Pt multilayers. (C) 2010 Elsevier B.V. All rights reserved.