El Sidrón cave in Spain holds remains of Neanderthal social group dated 49,000 years ago. All identified individuals preserve DNA due to site conditions. Anticontamination measures enable palaeogenetic studies on every individual. Samples reveal kinship relationships within Neanderthal groups. Data quantify internal genetic diversity of Neanderthals. Provide first empirical data for Neanderthal demographic models. Bone samples yield nuclear genes for pigmentation traits. Genes recovered for blood group phenotypes. Nuclear genes found for language-related traits. Genes identified for taste perception. Retrieved 0.1% of Neanderthal nuclear genome. Specimens suitable for future Neanderthal genomic diversity project.