A system and method for indexing and annotating use cases and generating test scenarios using in-memory processing from the corresponding use case model includes a use case model creator to create/build an in-memory use case model for the use cases created by a user; a predetermined structural format, according to which the steps of the use cases are organized by an editor; an indexer to appropriately index the steps of the use case(s) in the use case model; a generator which facilitates extraction of the indexed steps from the use case and identification of at least one ordered set in which the indexed steps can be assembled; and a test scenario generator to generate a test scenario having the indexed steps arranged according to the ordered set identified by an identifier and being validated by a validator according to pre-determined validation criteria.