The Two-Track Model of Bereavement Questionnaire (TTBQ) was designed to assess response to loss over time. Respondents were 354 persons who completed the 70-item self-report questionnaire constructed in accordance with the Two-Track Model of Bereavement. Track I focuses on the bereaved's biopsychosocial functioning and Track II concerns the bereaved's ongoing relationship to the range of memories, images, thoughts, and feeling states associated with the deceased. Factor analysis identified 5 factors that accounted for 51% of the variance explained. In accord with the theoretical and clinical model, 3 factors were primarily associated with the relationship to the deceased (Track II): Active Relational Grieving, Close and Positive Relationship, and Conflictual Relationship; and 2 factors with aspects of functioning (Track I): General Biopsychosocial Functioning and Traumatic Perception of the Loss. Construct and concurrent validity were examined and were found satisfactory. Differences by kinship, cause of death, gender, and time elapsed were examined across the 5 factors, the total TTBQ, and the ITG. The new measure is shown to have both construct and concurrent validity. Discussions of the results and implications for the measurement of response to loss conclude the article. (Contains 6 tables, 1 figure, and 1 footnote.)