General Practitioners (GPs) from underdeveloped countries apply cognitive impairment (CI) assessment tools translated and adapted to cultural setting from other idioms, mainly English. As schooling in elderly from underdeveloped countries tends to be relatively heterogeneous, it is necessary to establish normative and cut-off scores for these CI instruments that are based on studies conducted locally. Some CI screening instruments frequently used by Brazilian specialists in dementia were analyzed to determine which could be most useful to GPs in their working sets. Two hundred forty-eight patients aged 65 years or older that had been assisted by GPs in a tertiary hospital in Brazil were evaluated. Based on the MMSE and/or Short-IQCODE scores, 52 probable cases were identified on the basis of clinical data, performances on the neuropsychological tests and questionnaires (Functional Assessment Questionnaire/FAQ, Category Verbal Fluency/CVF, Clock Drawing Test/CDT) and blood tests and brain CT. The combination of a functional questionnaire with a cognitive instrument had higher sensitivity and specificity than using the instruments alone. A FAQ cut-off of 3 in conjunction with a CDT cut-off of 6 proved optimal (93% sensitivity and 92.5% specificity). A higher specificity (93.5%) was attained using a combination of the FAQ (cut-off of 3) with the CVF (cut-off of 10). For low schooling elderly, the combination of the FAQ and CVF represented a very simple method of increasing the chances of correct screening. For those with higher schooling, the combination of the FAQ and CDT was more suitable.