The program of mass inoculation of adults in Oakland County, Michigan, with monovalent influenza A/New Jersey/76 virus vaccine was monitored. A stratified random sample of participants was selected, and telephone interviews were conducted two days after inoculation. The group of vaccines differed from the overall county population in that it had a higher percentage of females and more of the vaccinees were older, better educated, and of higher income. Minor complaints following vaccination were relatively frequent, particularly sore arm. All complaints were significantly more frequent in females than in males, and among females, the group younger than 40 years reported these complaints most often. Since neither utilization of the vaccine nor complaints following vaccination were uniformly distributed, it was concluded that population-based studies are needed for proper assessment of vaccine-related effects.