Primitive meteorites contain a wide range of materials and components. Some are rare and tiny, e.g. presolar grains, others consist of various types of inclusions, and components such as chondrules and matrix with distinct mineralogical, chemical and/or isotopic characteristics. Isotope analyses of meteorites and their components have become a powerful tool in the interpretation and assessment of the origin and formation processes of primitive meteorites. Advancements in analytical instrumentations are driving the gathering of more precise and detailed isotopic data. There is widespread evidence for isotopic variations of different origins in stable isotopes. Well known and most pronounced, for example, are variations in oxygen isotopes, which are probably due to physicochemical processes in the protoplanetary disk. In addition, a number of stellar nucleosynthetic effects have been shown for neutron-rich isotopes carried either in tiny phases or determined in whole-rock samples. These findings have led to the recognition that the inner Solar System was isotopically less homogeneous than previously thought. Radiogenic chronometers, especially short-lived decay systems such as ²⁶Al-²⁶Mg and ⁵³Mn-⁵³Cr, allow us to constrain the timing of processes related to the formation of primitive meteorites and their components