Objective: To evaluate the feasibility in children of an intensive prospective data monitoring methodology for identifying precipitating conditions for migraine occurrence. Background: Migraine headaches are a common pain condition in childhood and can become increasingly chronic and disabling with repeated episodes. Identifying conditions that forecast when a child's migraine is likely to occur may facilitate next-generation adaptive treatments to prevent future migraine attacks. Methods: In this cohort study of a sample of 30 youth (ages 10-17) with migraine recruited through a pediatric headache clinic, smartphones supplemented with wearable biosensors were used over a period of 28 days to collect contextual data thought to be potentially relevant to headache occurrence. Self-reported data on headache occurrence, lifestyle, and perceptions of the environment were collected in 4 epochs per day using custom real-time reporting software. Data derived from the wearable biosensor included information on autonomic arousal and physical activity. Built-in sensors on participants' own phones also were used to indicate location and to quantify the sensory environment (e.g., ambient noise and light levels). Data fidelity was monitored to evaluate feasibility of the methods, and participant acceptability was assessed via an end-of-study survey. Results: Self-report data were obtained on a mean of 88.9% (24.9/28) of assigned days (SD = 22.4%) and at a mean of 68.9% (77.2/112) of assigned moments (SD = 24.5%). Data from the wearable biosensor were obtained for a mean of 18.7 hours per day worn (SD = 2.3 hours), with participants on average wearing the sensor on 20.3 days (SD = 9.9). Fidelity of obtaining objective data from phone sensors on the sensory environment and other environmental conditions was highly variable, with these data obtainable from 5 to 22/30 (16.7%-73.3%) of participants' own phones. Most participants (63.3%-100%) responded with at least "somewhat agree" to questions about acceptability of the study methods. However, 5 to 7/30 (16.7%-23.3%) patients indicated difficulties with burden and remembering to wear the sensor. Almost all participants (29/30, 96.7%) agreed that they would want information about when a migraine might occur. How to cite this article: Connelly MA, Boorigie ME. Feasibility of using "SMARTER" methodology for monitoring precipitating conditions of pediatric migraine episodes. Headache.