Introduction. Stigma and discrimination against patients with mental illness is very common amongst the society. Therefore, this study aims to study the knowledge and understanding of mental illness and attitudes to patient with mental illness, among the general population.Goal. To assess the knowledge and understanding of mental illness and attitude to patient with mental illness among population of Ulaanbaatar city and compare its results with a similar research in carried out in 2002.Methods. The study was conducted in Ulaanbaatar city from February to April, 2008 and included 991 people aged over 18 years. The sample was selected from 30 micro districts of Ulaanbaatar city, The method of sampling was using primary dot in first step, sampling households in mid step and selecting people by using method of Sweden key from household in final step. The study used 30 item standardized questionnaires. Also there were 2 extra cards to read for respondents.Result. Among the respondents, 45% were males and 55 % females. Average age was 37 years. In view of identifying negative attitude of patient with schizophrenia, majority of respondents answered as “loony person” (n=136) and “mad person” (n=83). Conclusion. Although there was stigma amongst the study population, 66% of subjects who were involved in study could give right diagnosis in non professional level and were able to identify symptoms of mental illness suggesting that more than half of the sample studied had some knowledge of mental illness.