In 1900 only 15% of world population lived in urban areas. In 2030 this percentage will rise to 60%. On May 23, 2007, according to data published by North Carolina State University and Georgia University, the overtaking took place: for the first time the urban population exceeded the rural. Over the last few years research on urban mental health has flourished, as significant contribution have been made in this expanding field. In this update we will summarize the latest developments in the field. First we will discuss the most important research approaches in urban mental health and then will discuss environmental as well as social determinants of urban mental health. The three most commonly cited approaches are the rural vs. urban approach, the intercity comparisons approach and the multilevel contextual model. More recently, Vlahov et als (Vlahov et als, 2005) summarized them as follows: the: urban health penalty, the urban sprawl model, the urban health advantage model and the urban living conditions model.The urban health penalty model posits that urban areas, due to unhealthy environments create the conditions for poor health. Thus, penalty stands foor higher rates of of medical problems, mental illness and substance abuse.For example, a recent German study found that higher levels of urbanization were linked to higher 12 month prevalence for almost all major psychiatric disorders (Dekker et als, 2008) Similarly, in the Netherlands five levels of increasing urbanization were significantly associated with increasing prevalence of psychiatric disorders. (Penn et als, 2007).