As medical providers seek new ways to control costs, online visits have begun to receive serious consideration. The purpose of this study was to compare the odds of being a cost outlier during a 6-month period after either an online visit or a standard drop-in visit in a conventional medical office setting. Medical records of primary care patients (both adults and children) seen in a large group practice in Minnesota in 2008 were analyzed for this study. Two groups of patients were studied: those who had an online visit (N = 390) and a comparison group who had regular office care for same-day, acute visits (N = 376). Case types were classified as either complex or common, with common being defined as treatment for pinkeye, sore throat, viral illness, bronchitis, or cough. Outliers were defined as patients for whom standard costs exceeded the 75(th) percentile during a 6-month period after the index visit. Multiple logistic regression analysis was used to adjust for differences between groups. The percentage of online visitors who were cost outliers was 21.2 (versus 28.5 in the standard visit group). Median standard costs were $161 for online visits and $219 for same-day acute visits. The adjusted odds of being a cost outlier was lower for the online visit group than for the standard visit group (odds ratio [OR] 0.52, 95% confidence interval [95% CI] 0.35-0.77) after adjusting for number of visits in the previous 6 months, age, sex, and case type. Outpatient visits in the previous 6 months were positively related to outlier status (OR 1.23, 95% CI 1.17-1.29). Online visits appeared to reduce medical costs for patients during a 6-month period after the visit.