Background: Mental health illnesses are major issues in Kano State, Nigeria. Therefore it is important for families to have the knowledge of mental healthcare illnesses, unfortunately, families lack knowledge of mental health education and that create negative beliefs and attitude about mental illness and that limit the optimal benefit of management to the patient. Objective: This cross-sectional study was conducted to evaluate relatives’ knowledge, beliefs and attitude on mental illness and place of treatment in Kano State. Methods: This survey was conducted during the period of 5th June to 30th September 2016, where adult relatives (aged >20 years) of mentally ill patients receiving treatment for the period of 2 – 5 years in Dawanau Mental Health Hospital in Kano were invited for the study. Data was collected through face to face interview and focus group discussion method using semi -structured questionnaire guide and analyzed descriptively. All analysis was performed using Statistical Package for Social Sciences (SPSS) software (version 21). Results: In all, 266 participated in the study, of which 216 (81.2%) were males. Almost three quarter of respondents their ages were <40 years and about 188 (70.7%) were residing in the city of Kano. 112 (42.1%) were university graduates. 132 (49.6%) of the subjects thought that evil spirit was the major cause of mental illness, followed by personal weakness 126 (47.4%). While majority of the respondents 196 (73.7%) preferred home treatment. Those who believed in spiritual treatment for mental illnesses were 192 (72.2%); of this number, 99 (51.6%) believed in Quran, and 88 (45.8%) on both Quran and herbs. In fact, majority 194 (72.9%) of the participants believed that medicines can treat the mental illness. Conclusions: The study showed that negative beliefs about the causes and signs of mental illnesses were rampant. Negative attitudes were also noticed among the respondents. There is a need for health education awareness and interventions in communities for a better knowledge of mental illness and good beliefs and attitude.