Vaccinating newborns against hepatitis B within 24 h of birth followed by two subsequent doses usually prevents mother-to-child transmission, but is demanding on health staff and systems especially in developing countries. To provide an evidence-base for guidelines on birth-dosing, a research study including key informant interviews, focus group discussions and surveys among community health workers and mothers of infants was conducted in four provinces of Viet Nam. The study aimed to elaborate different existing operational prototypes, their incremental operational costs and timeliness and coverage outcomes. Birth-dosing strategies were found to be location-specific and diverse. Vaccine storage site was the main determinant of the local birth-dosing mechanism and incremental cost, but not necessarily its timeliness and coverage. Major factors affecting birth-dose timeliness and coverage included community-based pregnancy tracking practices, relations of the immunization programme with private maternity services and large urban hospitals, perceived contraindications, and family perceptions. Future birth-dosing guidelines should specifically address the affects on timeliness and coverage identified.