Re-Os isotopes are used to determine the age of mineralization at Candelaria, Chile, and to explore possible genetic links with the batholithic intrusions in the area. Calculated Re-Os ages from molybdenite are 114.2 * 0.6 Ma and 115.2 * 0.6 Ma, and are interpreted to represent the age of mineralization. An isochron calculated by Re-Os ratios from hydrothermal magnetite and sulfides constrains an initial 187Os/188Os of 0.36 * 0.10. These values are broadly similar to the calculated initial 187Os/188Os for magmatic magnetite in nearby batholithic rocks that range from 0.20 to 0.41. The relatively radiogenic initial 187Os/188Os represents a mixture of mantle and crustal components in the ores and batholitic rocks. The similarity in initial 187Os/188Os of the ore and magmatic oxides suggest that the granitic plutons could be the source for metals in the Candelaria district. In order to establish a regional perspective, we analyzed ore minerals from other Chilean deposits of the iron oxide (Cu-U-Au-REE) class. Magnetite from the Manto Verde iron oxide Cu-Au deposit has Os and Re concentrations of 11 to 17 ppt and 4 to 6 ppb, respectively. The initial 187Os/188Os is approximately 0.20 and similar to that of ore minerals from Candelaria, and to the Early Cretaceous batholithic intrusions. These data indicate a similar metal source for the mineralization at Manto Verde and Candelaria. Magnetite from three magnetite-apatite deposits of the Chilean Iron Belt have Re concentrations between 0.8 and 3 ppb and Os concentrations between 11 and 76 ppt. Calculated initial 187Os/188Os of these magnetites range from 1.2 to 8.4, and are different from those of the iron oxide Cu-Au deposits. The cause of the comparatively high radiogenic signatures in the magnetite-apatite ores could be related to fluid interactions with the surrounding sedimentary rocks during their genesis. In contrast to the iron oxide Cu-Au systems, the Os in magnetite-apatite ores could be derived from sedimentary rocks.