During one morning in 1992 in Niamey, Niger, interviews with 380 women aged 15-49 attending five health facilities and with persons bringing 209 infants (0-11 months) to the same centers were conducted to identify weaknesses in the Expanded Program for Immunization in Niger and to define strategies to improve services. Missed opportunities for vaccination were used to evaluate these services. The health facilities were a maternal and child health (MCH) center, a dispensary, a national family health clinic, a social security health center, and a pediatric service at a central hospital. 27% of the infants lacked at least one vaccination. The corresponding figure for the women was 39%. The major types of visits were well-baby visits (45%) and curative visits (32%). The types of child vaccinations missed were all three DPT (diphtheria, pertussis, and tetanus) doses (30% for 1st, 23% for 2nd, and 27% for 3rd), measles (29%), yellow fever (27%), and BCG (15%). Among women, the third and fourth doses of tetanus toxoid were most missed (31% and 23%, respectively). 87% of the persons accompanying the infants and 86% of the women would have accepted the vaccination on the day of the survey had it been made available. Among infants, missed opportunities were more common at the social security health center (56%) and least common at the national family health clinic (5%). Among women, the MCH clinic and the dispensary missed opportunities to vaccinate the most (59%) followed by the national family health clinic (53%), the hospital (47%), and the social security clinic (33%). 88% of persons with the infants had the infant's vaccination card with them. On the other hand, only 9% of women had their vaccination card. Based on these findings, some recommendations were: guarantee a supply of vaccination cards for all women; systematically distribute cards to women aged 15-49 and inform them of the importance of bringing it with them when they visit health services; provide vaccinations every day in all health facilities; and re-evaluate vaccination stocks.