Women in many countries are often denied vital family planning services if they are not menstruating when they present at clinics, for fear that they might be pregnant. A simple checklist based on criteria approved by the World Health Organization has been developed to help providers rule out pregnancy among such clients, but its use is not yet widespread. Researchers in Guatemala, Mali, and Senegal conducted operations research to determine whether a simple, replicable introduction of this checklist improved access to contraceptive services by reducing the proportion of clients denied services. From 2001 to 2003, sociodemographic and service data were collectedfrom 4,823 women from 16 clinics in three countries. In each clinic, data were collected prior to introduction of the checklist and again three to six weeks after the intervention. Among new family planning clients, denial of the desired method due to menstrual status decreased significantly from 16 percent to 2 percent in Guatemala and from 11 percent to 6 percent in Senegal. Multivariate analyses and bivariate analyses of changes within subgroups of nonmenstruating clients confirmed and reinforced these statistically significant findings. In Mali, denial rates were essentially unchanged, but they were low from the start. Where denial of services to nonmenstruating family planning clients was a problem, introduction of the pregnancy checklist significantly reduced denial rates. This simple, inexpensive job aid improves women's access to essential family planning services.