Reliable U-Pb isotope dating of hydrothermal ore deposits and events in their host terrains are being advanced by new developments and analytical techniques. Precambrian deposits and terrains, in particular, are best dated using U-Pb methods applied to U-bearing minerals which form during ore formation and other geological events. The REE-phosphates monazite and xenotime, appear common, although minor, in most hydrothermal systems, and are more isotopically robust than all(?) other datable minerals. However, due to the typically small grain size of these minerals, advanced SIMS-based (secondary ion mass spectrometry) geochronology, coupled with a detailed understanding of the petrography of the samples within a paragenetic framework of ore deposition, has emerged as the best and most flexible approach to reliable geochronology of hydrothermal ore deposits. Herein we outline the status of SIMS-based geochronology and petrology of ore deposits and environs, and highlight some recent examples for gold, iron and uranium deposits and their host terrains.