A survey was conducted in early 1990 in areas served by the University Center for Public Health in the prefecture of Butare, Rwanda, to determine the knowledge, opinions, and behaviors of parents regarding vaccination and to evaluate the influence of knowledge on vaccination coverage. A qualitative questionnaire was administered to 65 mothers, 3 fathers, and 3 grandmothers of children aged 1-3 years. 52 of the mothers were cultivators, 8 were petty merchants, and 5 were employed. All the parents knew that a vaccination is a preparation administered to a healthy person in the hope of protecting against a disease. 10% of respondents knew 3 illnesses that are targets of the Expanded Program of Immunization, 18% knew 4 illnesses, 27% knew 5, and 45% knew 6. 56% knew that 1 of the vaccines is trivalent and recognized the 3 diseases it protects against. 69% of respondents believed that vaccinations should be administered at 1 month, 9 months, and 18 months. Only 20% knew the correct vaccination schedule. 7% knew only 1 vaccination date and 4% did not know way. 49% of respondents knew that vaccinations might lead to fever, 24% of fever and swelling, 10% to swelling, and 17% to pain at the injection site. 16% had observed abscesses. None of the respondents doubted the efficacy of vaccines. 90% of respondents had their children vaccinated to avoid diseases, 4% to satisfy the communal authorities, 4% for the good of the child, and 2% because others did so. The most important source of information about vaccination was the health agent, followed by radio broadcasts. 93% of respondents reported they had no difficulty in having their children were incompletely vaccinated cited difficulties including being alone in the household, distance to the vaccination center, illness and works as reasons. It appears clear that knowledge of vaccination on the part of parents is not an important factor in vaccination coverage. The current level of coverage is acceptable, and future measures should focus on maintaining and improving coverage rather than on education.