The proposed research will investigate the role of mindfulness in mother-infant relationships and how this impacts biological aging. Telomeres, the repeated nucleotide sequences at the end of chromosomes, protect chromosomes from deterioration and enable cellular integrity. Age, relational stress, and inflammation degrade telomeres, which in turn is thought to relate to a range of health risks (i.e., physical disease and early mortality). Mindfulness has been associated with increased telomerase, the enzyme that maintains and repairs telomeres, but this has not yet been investigated in a relational context. We propose to assay telomere length in mother-infant dyads (n = 60) involved in a pre-existing longitudinal study at the University of Oregon. Funding through the Mind and Life 1440 Award would allow for these assays of mother and infant saliva samples. This study will allow us to 1) define normative rates of telomere shortening across the first postnatal year, 2) elucidate how mother and infant neuroendocrine stress reactivity impacts the degradation of telomeres across the first 18 months of life, and 3) determine whether maternal mindfulness acts as a protective factor in both mother and infant biological aging.