It has been hypothesized that, in species exhibiting natal philopatry, genetically related individuals would have home ranges closer to each other than those of unrelated individuals. Using radiotelemetry (2001–2003) and genetic data from 35 female Florida black bears (Ursus americanus floridanus), we tested the hypothesis that genetic relatedness among individuals influenced the spatial organization of home ranges. Genetic relatedness was negatively correlated with geographic distance between home ranges for each year and season (except autumn 2000), suggesting that genetically related individuals established home ranges closer to each other, whereas home ranges of unrelated females were geographically separated. Additionally, females that had overlapping core home ranges were more closely related than females whose home ranges did not overlap. These results are consistent with the hypothesis that genetic relatedness influences spatial organization of home ranges.