Dental morphology is a useful resource in archaeology, anthropology and paleontology, due to its genetic determination. Teeth are a material of high durability and stability. This work aims to study the dental morphology and test the Portuguese and European biological affinities of an undocumented mandibular sample, through comparison with global and Iberian samples. The dental traits in 163 mandibles (kept at the Museum of Natural History of the University of Oporto, Portugal) were scored using a standardized methodology (ASUDAS: Arizona State University Dental Anthropology System) and compared to other world-wide and Iberian samples through Principal Components (PCA) and Mean Measure of Divergence analyses. The undertaken quantitative and statistical tests demonstrated the unknown sample to be closer to the Coimbra Portuguese sample in all three comparisons. This suggests this undocumented mandibular sample is possibly of Portuguese 19th/20th century origin.