The Christian Medical College and Hospital (CMCH) is a referral hospital with a well established referral microbiology laboratory. There is a good system of documentation of all laboratory records in the Department of Microbiology. Our study has shown that there is a seasonality in V.cholerae and also that there is a significant association between rainfall and V.cholerae over these years. However, this association was notsignificant in the later part of the study period, that is, from 2005 to 2010. This may be due to the power of the study, insufficient time period, due to changes in the drainage system, availability of good quality drinking water by the government or due to the evolution of the bottled water industry since 2004.