Despite being a routinely administered assessment of grieving, few studies have empirically examined the psychometric properties of the Core Bereavement Items (CBI). The present study investigated the factor structure, internal reliability, and concurrent validity of the CBI in a large, diverse sample of bereaved young adults (N = 1,366). Exploratory and confirmatory factor analyses (conducted on randomly selected halves of the sample) supported a two-factor structure, with items tapping into grief-related Thoughts and Emotional Response to loss. These factors showed strong internal consistency and unique associations with demographic variables, circumstantial factors surrounding the loss, and a measure of prolonged/severe grief—highlighting the potential applicability of the identified factor structure.