Research on the effects of childhood trauma has been limited by the lack of a comprehensive, reliable, and valid instrument that assesses the occurrence of early traumatic experiences. This paper presents the development and preliminary psychometric properties of an instrument, the Early Trauma Inventory (ETI), for the assessment of reported childhood trauma. The clinician-administered ETI is a 56-item interview for the assessment of physical, emotional, and sexual abuse, as well as general traumatic experience (including items which range from parental loss to natural disaster). For each item of the ETI, frequency of abuse/trauma by developmental stage, onset and termination of abuse/trauma, perpetrator of the abuse/trauma, and impact on the individual are assessed. Initial analyses indicate acceptable inter-rater reliability, test-retest reliability, and internal consistency for the ETI. Comparisons between the ETI and other instruments for the assessment of trauma, as well as instruments for the measurement of symptoms related to abuse, such as dissociation and PTSD, demonstrated good convergent validity. Validity was also demonstrated based on the ability of the ETI to discriminate patients with PTSD from comparison subjects. Based on these findings, the ETI appears to be a reliable and valid instrument for the measurement of reported childhood trauma. Depression and Anxiety 12:1–12, 2000. © 2000 Wiley-Liss, Inc.