Delhi was the fourth State in India to conduct mass immunization of children (Pulse Polio Immunization) of the < 3 year age group with Oral Polio Vaccine (OPV) as a strategy towards the eradication of poliomyelitis. This study attempted to evaluate the immunization coverage achieved and the channels of communication which were effective in increasing coverage in three high risk areas of Delhi during October 1994. The overall immunization coverage was 89%. Information sources like enumeration visits, posters, television, radio and schools statistically correlated with the Pulse Polio Immunization (PPI) outcome. However, the cost of enumeration was high. Other less expensive channels of communication appeared to be equally effective. Only 11% of the children surveyed were not immunized with PPI OPV. The major reasons why some children did not receive OPV was that parents were "not informed" or they were "too busy".