Background: The Women, Infants and Children(WIC)program and emergency care sites have been emphasized in efforts to improve immunization rates. The potential for primary care to increase population immunization rates needs to be more fully examined.Objectives: To assess missed opportunities (MO) for immunization in diverse primary care settings from a survey of randomly selected children in Norfolk, VA. Methods: 389 children selected through cluster sampling of Norfolk households in 1993 were recontacted 6 months later to obtain authorization to request records from all health care providers of children seen by 2 yrs, including WIC, primary care and emergency services. Provider records, including all sources of care, were obtained and reviewed for 269 (69%) children. MO was defined as a health care visit at which a child was not immunized but eligible based on CDC guidelines. Clinical visits were not considered MO if associated with fever (temperature ≥38.4° C). Up-to-date (UTD) immunization was assessed from parent and provider records.Results: From 0-2 yrs of age, children made 4343 visits to public, private and military providers for immunization, well-child, acute and emergency care (range=2-54, mean=17 visits/child); 1492 (34%) were MO. A total of 3368 (78%) of all health care visits were for primary care (mean=13 visits/child by 2 yrs of age), 1131 (34%) of which were MO. There was no difference in MO rate by type of primary provider (private practice, hospital ambulatory clinic, military clinic or public health clinic). Among MO in primary care, most occured in cases lacking any significant clinical obstacle: 167 (15%) occurred to healthy children during well-child or follow-up visits; 209 (18%) during visits for afebrile upper respiratory infection, and 288(26%) for afebrile otitis media. Overall, 70% of children were UTD at 12mo, 59% at 24 mo. Had MO not occurred, an additional 16% of children at 12 months and 20% at 24 months would have been UTD. 76% of MO occurred during primary care visits. Conclusions: The majority of MO occurred during routine well-child and uncomplicated acute care visits regardless of the type of primary care provider. MO in primary care should be targetted to increase immunization rates in the pediatric population. Funded by CDC National Immunization Program