The source, the removal and the mechanical consequences of the non-metallic inclusions depends on their types and on their engineering. The chemical composition of the non-metallic inclusions and their volume fraction are determined by the management of the different steps involved in the production process: melting, refining and casting operation. Thus, the inclusional population depends on the relation existing between the applied operative parameters and the features of the steel grades to be produced. A synthetic and critical evaluation of the main aspects involved in the control of the non-metallic inclusions has been presented pointing out the main aspect for the designing of a correct production route and the consequences on the application field.