Infectious bronchitis is an acute and highly contagious respiratory disease of chickens characterised by respiratory signs comprising gasping, coughing, sneezing, tracheal rales and nasal discharge. In addition, severe respiratory distress may occur in young chickens. Respiratory distress, decrease in egg production, and loss of internal egg quality and egg shell quality have been reported in layers. Some strains of the virus produce severe kidney damage and may be associated with high mortality. Moreover, this pathology is considered to have worldwide distribution, so it is not contro-lled totally. Knowing its most hazardous features is required to minimise the great impact which has in poultry farming. According to the current situation, it is essential to review and update this severe problem. The authors have developed a complete review in a didactic and graphic way, including images, tables, graphs, etc., accompanied by a short text, to make the handbook more understandable and affordable. This precise information will help the veterinarians to know everything about this topic and tackle it properly.