This paper describes the transformation of UML static diagrams into B for verifying the consistency of UML properties. Class diagrams, object diagrams and OCL constraints are transformed into B abstract machines which are then combined into a complete B specification. UML object diagrams provide the data, meanwhile constraints on associations in class diagrams and constraints expressed by OCL give invariants for the B specification. Proof obligations automatically generated by the support tool (AtelierB) are used to check the consistency of UML specifications.