The most important compositional and group-structural characteristics of resins and asphaltenes from 13 heavy crude oils of different oil-bearing regions and four natural bitumens of Kazakhstan fields have been determined, It has been established that the values of most of the parameters fall within the ranges found earlier for resins and asphaltenes from normal (light and medium) crude oils, The general changes in the composition and structure of resins and asphaltenes according to the conditions of occurrence of the crude oils are similar. The ranges of variation in all the compositional and structural parameters of resins and asphaltenes overlap. The known consistent differences between these groups of crude oil components become clear only when average values of the parameters are compared. The high capacity of the resins and asphaltenes for intermolecular dissociation with the formation of a complex, of polymolecular aggregates, of ＇＇pack＇＇ particles and of micelles gives the crude oils and bitumens the properties of polydispersed, dynamically equilibrium systems, the state of which changes considerably under the influence of external factors.