The purposes of this study were to develop and validate a measure of unmet resource needs of the caregivers of survivors of stroke and to describe the caregivers’ unmet needs during 1 year. A longitudinal, descriptive design was used to test the reliability and validity of the Unmet Resource Needs (URN) measure. Item development was based on literature review and preliminary study findings. A stress and coping conceptual model framed the hypotheses. Psychometric testing was based on 6-month postdischarge data (n = 166). Content and structural construct validity, internal consistency reliability through 1 year, and concurrent validity were tested. Change in URN over time was examined. Content validity was supported by floor and ceiling effects less than 5%. Principal axis factoring yielded a 12-item, two-factor solution reflecting general and technology unmet needs. Internal consistency reliability was satisfactory for the total scale and subscales at all times, excepting the baseline three-item technology scale (α = .56). Concurrent validity was supported by significant correlations with model constructs (threat, positive problem solving, depression, preparedness; p < .01) in the expected direction. Functional status and resource use were not associated with the URN. Repeated measures analysis of variance (n = 123) indicated a significant decrease in unmet needs from baseline to 3, 6, and 12 months postdischarge (p < .001). Nevertheless, 42% reported one or more unmet needs at year 1. Assessment and counseling on unmet needs is indicated throughout the caregiving trajectory to reduce negative outcomes.