There is scant data on the casemix and practices in Indian intensive care units (ICUs). Most of the available data comes from single centre studies. There is a dire need to have data from Indian ICUs to reflect the vast spectrum of critical care illness, services and practices. INDICAPS planned to collect data of all patients in the ICU on one particular day, and four such days spread throughout a one-year period were selected: the second Wednesday of July and October this year, i.e. July 14 and October 13, 2010 and the second Wednesday of January and April next year, i.e. January 12 and April 13, 2011. As many ICUs all over the country as possible were asked to participate. The investigators aimed to gather information about ICUs, patients in ICUs, the types and severity of illness, monitoring and therapeutic modalities used, types of infections,mortality rates, etc.