Enhanced hard magnetic properties were obtained in nanostructured PrCo5 and YCo5 intermetallic compounds processed by mechanical milling for 240 min, and subsequent annealing in high vacuum at 1103 K for 1.0 and 2.5 min, respectively, followed by quenching in water. X-ray diffraction data demonstrate that the annealing has produced an average grain size <D> below 20 nm for both compounds, as a consequence magnetic measurements at room temperature showed a coercivity (HC) higher than 0.79 MA/m, and enhanced remanence (σr /σmax>0.5). High temperature magnetic measurements showed a temperature dependence of HC and remanent magnetization σr for both compounds, where the temperature coefficient of coercivity for PrCo5 is bigger than for YCo5. Such behavior is consistent with the intrinsic temperature variation of magnetocrystalline anisotropy for PrCo5 and YCo5 intermetallic compounds.