The dialkyl- or alkyl/aryl esters of 1,2-benzenedicarboxylic acid, commonly known as phthalates, are high-production-volume synthetic chemicals and ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate in the environment. Humans are exposed to these compounds through ingestion, inhalation, and dermal exposure for their whole lifetime, since the intrauterine life. Public and scientific concern has increased in recent years about the potential health risks associated with exposure to phthalates. The main focus has moved away from the hepatotoxic effects to the endocrine disrupting potency of these chemicals. To date, although the consistent toxicologic data on phthalates is suggestive, information on sources and pathways of human exposure to phthalates is limited. Recently, exposure to phthalates has been assessed by analyzing urine for their metabolites. This approach is contrary to the determination of the parent phthalates in air, water and foodstuff and not subject to contamination. Furthermore, these metabolites and the parent phthalates are considered the toxic species. However, accurate methods and models for measuring the amount of phthalates absorbed by the various pathways of exposure have to be developed. In fact, a frequent biological monitoring of phthalates in body fluids and tissues would be highly advisable, both in helping physicians to perform health risk assessments for exposure in the general population and in guiding governments to provide regulations concerning the maximum allowed concentrations in the environment, plasticized products, medications and medical equipment.