Background: There are known sex differences in presenting symptoms and outcomes of stroke patients, yet little is known about sex differences in patients with transient ischemic attack (TIA). Our aim is to conduct an exploratory study of sex differences in symptoms, clinical characteristics, and outcomes among patients admitted to an ED observation unit (OU). Methods: Patients seen in a large, urban, academic ED with a diagnosis of TIA and admitted to the ED OU between 4/13 and 3/14 were included. Patients were excluded if they had persistent neurological deficits, fever >100.4, heart rate <60 / >100 bpm, SBP >180 / < 100 mm Hg, pulse ox <93%, or other competing ED diagnoses. Patients were evaluated using standard blood tests, EKG, echocardiogram, ED MRI/A of the head and neck, and neurology consultation. Using bivariate analyses, women and men were compared with respect to presenting symptoms, risk factors, acute infarct on MRI/A, and recurrence of symptoms. The study was approved by the hospital IRB. Analyses were conducted using Stata 12.1. Results: 136 patients met inclusion criteria; 52.2% were women. Women and men were similar in mean age (63.8, 95% CI 59.2 - 68.4, vs. 65.4, 95%CI 61.7 - 69.0) and percent non-white (22.5% vs. 24.6%, p=0.78). More women than men reported motor symptoms (53.5% vs. 30.8%, p=0.007), while more men reported visual changes (24.6% vs. 9.9%, p=0.02), dizziness (30.8% vs. 19.7%, p = 0.14), and symptoms coded as ‘other’ (36.9% vs. 22.5%, p=0.07). Women had longer median times of symptom duration (60 min, IQR 10 - 120, vs. 30 min, IQR 10 - 90). 25.5% of women vs. 22.0% of men had acute infarcts on MRI/A (p=0.68), and 5.7% of women compared to 1.5% of men reported recurrence of symptoms at 30 days (p=0.21). Conclusions: In our exploratory study of sex differences in ED TIA patients, women were less likely to report “non-traditional” symptoms, a finding contrary to current literature in stroke patients. Although these findings should be investigated in future studies of TIA patients, this may suggest an inherent bias in those referred to an ED TIA OU. Future studies should investigate potential sex differences in disposition to admission versus observation unit after TIA, cerebral distribution of acute vascular event, and the recurrence of symptoms.