In this chapter, the application of computational techniques in environmental exposure assessment was described. The most important groups of these techniques are Multimedia Mass-balance (MM) modelling and Quantitative Structure-Activity/Structure-Property Relationships (QSAR/QSPR) modelling. Multimedia Mass-balance models have been widely utilized for studying Long-Range Transport Potential (LRTP) and overall persistence (POV) of Persistent Organic Pollutants (POPs), regulated by many national and international acts, including the Stockholm Convention on POPs. Recently, a novel modelling methodology that links QSPR and MM has been implemented. According to this approach, the physical/chemical properties required as the input variables for multimedia modelling can be calculated directly from appropriate QSPR models. QSPR models must be previously developed based on the relationships between the chemical structure and the modelled properties (QSPR).