Aims:To evaluate the validity of three questionnaires used by community health workers and auxiliary nurses for psychiatric screening in primary health care (PHC) in Brazil.Method:Training for administrating the SRQ-20, WHO-5 and COOP/WONCA Charts was given by a consultant psychiatrist to community lay workers and auxiliary nurses working in four PHC teams in university community health center. The questionnaires (administered by 14 community lay workers and auxiliary nurses) and a semi-structured psychiatric interview (SCID - administered by the consultant psychiatrist blind to the patients results on questionnaires) were held with 120 PHC patients who were at least 15 years old. Predictive validities of SRQ-20, WHO-5 and individual items of COOP/ WONCA charts in relation to SCID were calculated through area under ROC curves (AUC) and total accuracy. Concurrent validities between questionnaires were calculated through spearman coefficients.Results:For SRQ-20 (20 questions): AUC = 0.92; total accuracy on cut-off 7/8 = 85%. For WHO-5 (5 questions): AUC = 0.90; total accuracy on cut-off 11/10 = 85%. For COOP/WONCA chart “feelings”: AUC = 0.88; total accuracy on cut-off 2/3 = 85%. Sperman coefficients between SRQ and COOP/WONCA chart “feelings” was 0.74; between WHO and “feelings” was 0.67.Conclusions:Results of COOP/WONCA Chart “feelings” - an individual item of a questionnaire specifically developed for use in primary health care - were as good as more extensive questionnaires specifically developed for psychiatric screening purposes.