Infectious bronchitis virus (IBV) has characteristics of rapid spread and evolution. In recent years, a number of variants have been detected and classified into diverse genogroups. There is nearly no cross sero-protection among these variants. This review summarizes the epidemiology situation of IBV strains and variants on a geographic basis. Particularly, in Taiwan, IBVs have evolved independently to Taiwan Group I and Taiwan Group II. QX IBV, one of the variants originated from China, has widely spread in Europe and Asia but not been discovered in Taiwan.