The 1999 version of ACI code - 318 introduced a new approach for the verification of cracking in reinforced concrete elements in bending, which radically changes the past practice of conditioning the good performance under service loads to the opening of the cracks values exceed certain limits, dependent on the characteristics of the aggressiveness of the medium. To control cracking, since the NC-53-39-97, introduced in Cuba in the ACI approach for the verification of State Limit of Crack Widtht, so that these provisions are directly relevant to the community of professionals dedicated to structural design. As the crack control is key to a good project in Cuba, is essential to deepen in these provisions, questioning its applicability to the aggressiveness of a tropical climate. It discusses the advantages of the introduction of these news procedures, the need is made from a knowledge of their bases and they are carried out different proposals practices for their implementation in Cuban conditions.