The asymmetry of information is of key importance i n the housing market. This study presents a literature review that supports the rele vance of information asymmetry in real estate, divided into four distinct areas: price dis tortion in the housing market, information asymmetry and adverse selection, information asymme try and predictability of returns and asymmetric information and real estate depreciation . Based on the literature review a survey was sent out and answered by 330 commercial delegat es of the three largest Portuguese real estate companies. The authors conducted a descripti ve analysis and studied the differences statistically significant at the level of informati on considered by real estate agents by gender, school level, the performance of the full-time prof ession or part-time and also at the level of preference achievement of business with potential c ustomers, aiming to discover and analyze a set of interrelated variables and reduce the larg e number of variables in a smaller number of factors applied to factor analysis. The study concl uded that there are eight determinants of information asymmetry in real estate: negative exte rnalities, business opportunities, housing quality, service areas / storage, proximity to busi ness, rest and recreation areas, quality reputation and positive externalities.