The prevalence of childhood obesity has reached alarming rates world-wide. The aetiology seems to be an interplay between genetic and environmental factors, and a surrogate measure of this complex interaction is suggested as familial predisposition. Familial predisposition to obesity and related cardiovascular disease (CVD) complications constitute the presence of obesity and/or obesity-related complications in primarily blood-related family members. The approaches of its measurement and applicability vary, and the evidence especially of its influence on obesity and obesity treatment in childhood is limited. Studies have linked a familial predisposition of obesity, CVD (hypertension, dyslipidaemia and thromboembolic events), and type 2 diabetes mellitus to BMI as well as other adiposity measures in children, suggesting degrees of familial aggregation of metabolic derangements. A pattern of predispositions arising from mothers, parents or grandparents as being most influential have been found, but further comprehensive studies are needed in order to specify the exact implications of familial predisposition. In the scope of childhood obesity this article reviews the current literature regarding familial predisposition to obesity and obesity-related complications, and how these familial predispositions may impact obesity in the offspring.