Gadolinium nanoparticles have been produced at subambient temperature by alkalide reduction. The nanoparticles display maxima in the temperature dependence of their magnetization, cooled in the absence of an applied external field, at T-max of 5.0 and 17.5 K for unheated samples and samples annealed at 1000 degreesC for 4 h, respectively. Field cooled behavior deviates at temperatures slightly above Tax, increasing at lower temperature. Curie-Weiss law fits of the high-temperature data yield magnetic moments in close agreement with those expected for noninteracting Gd3+ ions, suggesting that the behavior seen is due to a magnetic transition rather than superparamagnetism. Magnetization is linearly dependent on field at temperatures higher than 7-8 times T-max and shows remanence-free hysteresis at lower temperature, suggesting metamagnetism. Some annealed samples show evidence of additional ferromagnetic interactions below similar to170 K. Magnetic entropy curves generated from magnetization data are consistent with that expected for a paramagnet.