Data on grandparental surnames were obtained from schoolchildren in 22 communes from Campobasso Province, Italy (Molise Region). The distribution of surnames was shown to be almost exactly linear by a log2–log2 transformation, which justified the fitting of the data to Fisher’s logarithmic distribution. The values for ν were higher among women. When ν was standardized to minimize bias due to sample size, the value was one-third the estimate of migration from exogamy data. The higher values of ν for females indicate that there is greater mobility of female marriage partners than males.