Therefore, scales with relatively few items can potentially minimize such problems and be useful in different testing settings (e.g., surveys and screenings), provided that they have acceptable reliability indices and satisfactory evidence of validity. Furthermore, a large number of items may impede the joint administration of two or more instruments. For example, very long instruments can induce discouragement, fatigue, and inattention in the participants. The literature shows evidence that a large number of items in an instrument can be a source of measurement error. Since the instruments for personality assessment tend to be extensive, usually consisting of more than 100 items, one of the research objectives in this area is the development of reduced scales (Carvalho et al., 2012 Hauck Filho et al., 2012a, b Natividade & Hutz, 2015 Passos & Laros, 2015). In addition to these, there are a number of instruments under development, either for research purposes or for future commercialization (e.g., Andrade, 2008 Carvalho, Nunes, Primi, & Nunes, 2012 Hauck Filho, Machado, Teixeira, & Bandeira, 2012a, b Gomes & Golino, 2012 Hutz et al., 1998 Natividade & Hutz, 2015 Passos & Laros, 2015 Primi, Santos, John, & De Fruyt, 2016 Vasconcelos, 2005 Vasconcellos & Hutz, 2008). Among the psychological instruments approved by the Federal Council of Psychology (Conselho Federal de Psicologia, 2017) and available on the Brazilian market, we can cite the NEO Personality Inventory - Revised (NEO-PI-R (Flores-Mendoza, 2007)), the Factorial Battery of Personality (Bateria Fatorial de Personalidade (BFP) in the original (Nunes, Hutz, & Nunes, 2010)), the Factorial Scale of Neuroticism (Escala Fatorial de Neuroticismo, in the original (Hutz & Nunes, 2001)), the Factorial Extraversion Scale (Escala Fatorial de Extroversão, in the original (Nunes & Hutz, 2007a)), and the Factorial Scale of Socialization (Escala Fatorial de Socialização (Nunes & Hutz, 2007b)). In Brazil, although the number of studies published using the FFM as reference is relatively small in comparison to other countries (Silva & Nakano, 2011 Passos & Laros, 2014), it can be stated that the development of instruments based on this model is increasing. The five-factor model (FFM), also known as Big Five, is currently one of the most influential and investigated models used in the personality research field (De Raad & Mlacic, 2015 McCrae, 2011). For Agreeableness and Conscientiousness, weaker evidence was found (raw correlations of. Moderate evidence of convergent validity was found for Extraversion, Neuroticism, and Openness to Experience (raw correlations ranging from. Correlations between the factors of both instruments were estimated. Both scales showed an adequate adjustment of the measurement model to the data (root mean square error of approximation < .06 standardized root mean square residual < .06) after excluding a number of items. The measurement model of each instrument was tested using confirmatory factor analysis. The two Brazilian scales were administered to 554 participants aged 16–69 years (M = 30.6, SD = 8.6). The objective of this study was to obtain evidence of the convergent and factor validity of the Reduced Scale of Big Five Personality Factors (ER5FP), with 20 items, and of the Reduced Inventory of Big Five Personality Factors (IGFP-5R), with 32 items.