The Clinical Practice Guidelines on asthma have contributed towards unifying concepts and reaching a consensus on performances between different professional groups. However, they have failed in the overall improvement in the management of asthma, the final objective that they are meant to achieve. Today, almost 20 years after they appeared, the majority of asthmatic patients are still inadequately controlled, partly due to lack of follow up by doctors and the rest of health care staff who have to look after them. This lack of follow up of these recommendations is probably associated with a lack of well structured planning in their circulation and implementation. Also, although the recommendations of these guidelines agree in what is essential, they differ in other aspects, which in turn could be determining factors in clinical practice. The purpose of this article has been to establish the main differences in the recommendations that the principal clinical practice guidelines on the disease propose on the diagnosis, classification and treatment of asthma. To do this we have compared, The British Guideline on the Management of Asthma 2007, The Global Strategy for Asthma Management and Prevention/Global Initiative for Asthma 2006 (GINA), the National Prevention program for Education on Asthma (Programa Nacional de Prevención para la Educación del Asma) (NAEPP), the Spanish Guide for the Management of Asthma (Guía Española para el Manejo del Asma 2003) (GEMA) and the ALAT y SEPAR guides, Latin-America and Spain. Recommendations for the Prevention and Treatment of Asthma Exacerbation (América Latina y España. Recomendaciones para la Prevención y el Tratamiento de la Exacerbación Asmática 2008) (ALERTA).