The aim of the study was to assess the status of routine immunization status and reasons for drop-outs in five districts in Bihar India. A community based cross sectional rapid survey in five districts in Bihar was undertaken from 11th January to 5th February 2013. Of the 38 districts in Bihar, 5 districts prioritized by the state government for intensive routine immunization support were selected purposively for the rapid assessment. Samples of primary health centres, Health sub centres, villages were chosen for the study using geographic and performance criteria. Twenty households having babies 0 to 36 months old from each village were randomly selected. A total of 7,500 households were taken from the 5 study districts. Apart from household survey, cold chain points where vaccines are stored and vaccination session sites were also assessed for service delivery and community participation. The assessment findings revealed high access resulted in good coverage of the initial vaccination such as BCG and DPT1, while low utilization due to drop out of children from DPT1 to DPT3 (15%) and BCG –measles dropout (27%). The coverage was inequitable, with 12% difference in full immunization among children below poverty line and scheduled caste and tribe children. The reasons for low vaccination coverage were both related to demand and supply side. Lack of awareness on immunization, lack of correct information about the place and time of immunization, illness of the child at the time of immunization session, irregular session timing and fear of adverse effects were found to be the major causes for almost 60% of households. The health staff ascribed it mainly to erratic supply of vaccines and logistics, poor planning, insignificant role of media or past experience of Adverse Effect Following Immunization (AEFI) as major causes. Based on the assessment of cold chain and vaccination session facility and key informant interviews, it was recommended that special emphasis should be given to due list preparation and tracking of beneficiaries using local volunteers, self-help groups and mobilizers especially in hard to reach areas. In addition, to ensure regular vaccine and logistic availability, Microplanning to include disadvantaged communities like Scheduled Caste (SC)/Scheduled Tribe (ST) & Below Poverty Line (BPL) households and intensive monitoring using both internal and external supervisors for regular monitoring of the routine immunization activities