PURPOSE: To make decisions about implementing systematic depression screening, primary care physicians who serve Spanish-speaking populations need to know whether Spanish language depression-screening instruments are accurate. We aimed to review systematically the evidence regarding diagnostic accuracy of depression-screening instruments in Spanish-speaking primary care populations. METHODS: We searched PubMed, PsycINFO, CINAHL, EMBASE, and Cochrane Libraries from inception to May 28, 2008, for studies examining the diagnostic accuracy of Spanish language depression case-finding instrument(s) administered to primary-care outpatients. Two authors independently assessed studies for inclusion and quality. RESULTS: Twelve studies met inclusion criteria. In general primary care screening, the Spanish language version of the Center for Epidemiologic Studies-Depression scale (CES-D) had sensitivities ranging from 76% to 92% and specificities ranging from 70% to 74%. We found no US study reporting the accuracy of the Primary Care Evaluation of Mental Disorders (PRIME-MD-9) or the Patient Health Questionnaire (PHQ-9) depression module in Spanish-speakers. One fair-quality European study and 1 poor-quality study conducted in Honduras found the 9-item PRIME-MD had sensitivities ranging from 72% to 77% and specificities ranging from 86% to 100%. The 2-item PRIME-MD was 92% sensitive, but only 44% specific for depression in 1 US study. In geriatric outpatients, the 15-item Spanish language version of the Geriatric Depression Scale (GDS) had sensitivities ranging from 76% to 82%, and specificities ranging from 64% to 98%. In postpartum women, the Spanish language version of the Edinburgh Postnatal Depression Scale (EPDS) was 72% to 89% sensitive and 86% to 95% specific for major depression (2 non-US studies). The Spanish language version of the Postpartum Depression Screening Scale (PDSS) was 78% sensitive and 85% specific for combined major/minor depression (1 US study). CONCLUSIONS: For depression screening in Spanish-speaking outpatients, fair evidence supports the diagnostic accuracy of the CES-D and PRIME-MD-9 in general primary care, the GDS-15-Spanish for geriatric patients, and the Spanish language versions of the EPDS or PDSS for postpartum patients. The ultrashort 2-item version of PRIME-MD may lack specificity in US Spanish-speakers.