Obesity is associated with elevated blood pressure (BP), insulin resistance, and altered plasma adiponectin levels; the relationship between the biochemical features of obesity and 24-h ambulatory blood pressure (24-h ABP) parameters in adolescents remains unknown. Anthropometric measurements and 24-h ABP monitoring were obtained on 41 obese adolescents with and without type 2 diabetes mellitus (T2DM). Serum adiponectin, high sensitivity C-reactive protein (hs-CRP), lipid profile, insulin, fasting glucose, liver enzymes, Hb A1c (HbA1c), and two random urine samples were obtained for creatinine and microalbumin measurements. The determinants of 24-h systolic (SBP) and diastolic (DBP) BP were examined using multivariate linear regression models with BP parameters as outcome variables. Forty-one obese adolescents were studied. Adiponectin levels were reduced and hs-CRP levels were elevated, and were inversely and significantly correlated (rho = −0.3, p = 0.05). ABP showed blunted nocturnal SBP dipping. Twenty-four hour SBP and DBP indexes were significantly (p < 0.05) and inversely correlated with adiponectin (rho = −0.4 and −0.42), respectively. In multivariate models, lower adiponectin level was independently associated with 24-h SBP and DBP. Adiponectin inversely correlate with ABP parameters in obese adolescents. Larger studies are needed to examine the relationship between adiponectin and mechanisms of BP regulation.