In the last few decades, the prevalence of allergic diseases, asthma, allergic rhinoconjunctivitis and atopic dermatitis in particular, has been observed to increase in urban settings. In addition, epidemiological data show the proportion of overweight individuals to rise in the last two decades. Obesity and overweight are a major public health problem not only in industrialized countries but also in developing ones because the morbidity and mortality rates are greater in the obese. An increased body mass index is considered a risk factor for the occurrence of myocardial infarction, stroke, atherosclerosis, hypertension, insulin resistance, dyslipidemia and some types of carcinoma. An ever greater body of available data point to the possible association of allergic diseases with obesity and overweight. Impaired immune tolerance is considered to be a sequel of immune changes due to the activity of adipokines, bioactive molecules secreted in white adipose tissue. About 50 adipokines are currently known to be secreted in adipose tissue, some of them belonging to the group of cytokines such as tumor necrosis factor alpha and interleukin-6. The association between obesity and allergic diseases has not yet been fully clarified. While the observations recorded to date should not be neglected, additional studies are necessary to help understand the complex function of adipokines involved in allergic events.