The human coronavirus (HCoV) contains HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV- HKU1, SARS-CoV and MERS-CoV. HCoV-229E, HCoV-NL63, HCoV-OC43 and HCoV-HKU1 are pathogens of common cold. During 2002-2003, a new coronavirus, the SARS-CoV, was found to be the cause of an acute, severe frequently fatal respiratory disease with prominent systemic symptoms (severe acute respiratory syndrome). The outbreak originated in south- ern China, probably following transmission from an animal in animal markets or bats to hu- mans. In 2012, some cases of novel coronavirus infection were reported in Arabian Peninsula with pneumonia and acute kidney injury. This novel coronavirus has been named Middle East respiratory syndrome coronavirus (MERS-CoV). The virus probably has come from camels and bats. I describe here about coronaviruses that have wide disease spectrum.from common colds to severe fatal illness as emerging infectious diseases.