A number of surveys, small or large, have been undertaken by various agencies for coverage evaluation of immunization programs. The most commonly used design is the WHO-30 cluster sampling method. Other new methods are the Institute for Refresh Medical Statistics (IRMS) New Delhi method and the lot quality assurance sampling method. This paper describes the National Immunization Day (NID) method to evaluate the immunization coverage of the Expanded Program on Immunization (EPI) vaccines in the Sunsari district of Nepal. A total number of 3,332 respondents (69.4% females and 30.6% males) were interviewed regarding the immunization status of their children during NID. The children with complete immunization (BCG, measles and three doses of DPT and OPV) were 65.7%. The individual coverage by EPI vaccines (except OPV III and measles) was more than 80%. The result shows that there is positive relationship between immunization coverage and educational level of the respondents.