Background: Valid assessment of the immunization status of children depends on access to immunization records. Frequently, the parent's record must be relied upon to assess the child's immunization history.Aim: The aim of this study was to assess factors associated with lack of availability of the parent-held immunization record in a household(HH) survey in urban E. Virginia. Methods: From 3/93-8/93, trained interviewers visited 13,000 HH which were randomly selected using multistage cluster sampling procedures. In HH with a 12 to 30 month old child, parents participated in a standardized 15 minute interview. Immunization status was determined from parent and medical records. Crude and adjusted odds ratio were calculated. Stratified and logistic regression analyses were performed to control for potential confounding factors. Results: Parents of 749(89% eligible) children were interviewed; only 54% could locate the child's immunization record. Lack of an immunization record at home was associated with 4.5-fold risk of the child not being up-to-date (UTD) with DTP, OPV and MMR vaccines at 12 months (P <.001) and 1.9-fold risk of not being UTD at 24 months (P =.03) controlling for potential confounding factors. Factors significantly (P <.05) associated with not having the child's record at home included being a teen mother; African-American ethnicity; and using a private vs. military or public provider. Military families were significantly more likely than others to have their child's record. Conclusions: Parental possession of their child's immunization record was associated with higher immunization rates, and varied by parent demographic factors and type of immunization provider. All providers should emphasize and update the parent's record. Due to the biased availability of parent records, population-based surveys should use provider records whenever possible.