The aim of this study was to analyze the prevalence of poor self-rated health according to socio-demographic variables and the presence of chronic diseases in the populations of Brazil and Portugal. A total of 13,894 individuals ≥ 30 years of age were studied in capitals in Northeast Brazil (VIGITEL 2011) and 20,579 in Portugal (4th NHI, 2005/2006). Poisson regression was used in both analyses of associations, adjusted by covariates. Net prevalence rates of poor health in men in Northeast Brazil and Portugal were 4.3% and 15.5%. Prevalence ratio was 2.72 (95%CI: 2.70-2.75) after standardization by age bracket. In women, prevalence was 8.1% in Northeast Brazil and 25.1% in Portugal (PR: 2.40; 95%CI: 2.39-2.42). The variable that showed the worst inequalities in poor self-rated health was schooling, in both Brazil and Portugal. Current disease had a stronger effect on Brazilians than on Portuguese, in both men and women. Prevalence of poor self-rated health was significantly higher in Portugal in all the groups analyzed.