Purpose: "Medication administration hassles" are the minor daily irritants that family caregivers experience when they assist a dependent family member with medication regimens. This study was designed to develop and test a multidimensional measure of the hassles in family caregiver medication administration. Design and Method: The authors employed a multiphase process (caregiver focus groups, instrument development, pilot testing, and field testing). Approximately 180 family caregivers representing diverse socioeconomic circumstances and racial or ethnic backgrounds participated in the study. The final version of the instrument consists of 24 items and four subscales: Information Seeking/Information Sharing (9 items, [alpha] =0.92), Safety Issues (5 items, [alpha] =0.83), Scheduling Logistics (7 items, [alpha] =0.90), and Polypharmacy (3 items, [alpha] =0.80). Overall scale reliability is 0.95, and test-retest reliability at 2 weeks is 0.84. Implications: Caregiver medication administration hassles represent a complex, multidimensional construct that warrants consideration in studies of contemporary family caregiver stress, strain, and burden.