In view of the growing proportion of immigrants and refugees in the population of Germany the knowledge on the influence of culture and migration on identity, and mental health presents a substantial basis for effective therapy. This article addresses important topics of psychotherapy with immigrants in general and with refugees in particular. Following issues selected according to their relevance and actuality are highlighted: definition of persons with migration background, migrants and refugees, facts on immigration to Germany, main results and theories on mental health of immigrants, social psychological aspects of intercultural psychotherapy (individualism vs. collectivism, stereotypes, discrimination etc.), psychosomatic diagnostics in intercultural context, diversity management in institutions, language and use of translators, living conditions of immigrants - stress and protective factors in immigrant mental health, post traumatic stress disorders among refugees: their prevalence, risk factors, diagnostics, course, multimodal psychosocial interventions in consulting centers, trauma focused interventions, trauma pedagogics, education and prevention of the volunteers.