Background: The independent association between sedentary behavior (SB) and physical activity (PA) is such that, regardless of accumulated PA, high amounts of SB are detrimental to health, even in adolescents. Purpose: Our aim was to profile activity patterns in free-living environments and to measure levels of SB and light (LT) and moderate (MOD) PA in obese adolescents via accelerometry. Methods: Participants wore Actical accelerometers on the right hip for at least 5 days, from 07:00 am to 11:00 pm. The number of minutes per hour of sedentary, LT, MOD, and vigorous (VIG) activity was calculated using established cut-points. Sixteen subjects (5 males, 11 females;14.8 ± 1.5 years) recorded at least 3 weekdays and 2 weekend days of accelerometry data. Results: Subjects spent a majority of time with SB (727.6 ± 101.2 min/d), followed by LT (212.4 ± 91.6 min/d) and MOD PA (20.5 ± 23.1 min/d). Subjects spent 75.6% of their waking day with SB. Discussion: In addition to low levels of PA, obese adolescents accumulated a substantial number of SB minutes. Translation to Health Education Practice: Minutes of SB are high among obese adolescents. Health educators should design interventions to reduce SB as a complement to programs designed to increase PA.