The objective of this study is to demonstrate the gravity of the Spanish flu in São Paulo city through the number of cases and deaths of the Brazilians and European immigrants. The data to the studied period were collected from the newspaper “A Gazeta” from 1918 and 1919. São Paulo had in 1918, 523,1961 inhabitants and 107,512 cases notified due to Spanish flu. The number of lethality was very high, the ratio varies in different outbreaks but in the city there were as much as to 4.5 deaths in 100 notified cases (4,814 deaths). For the city 0.99% of the population died, since October 15 until December 20 in São Paulo 1918. The peak of morbidity occurred after 21 days of the epidemic beginning and the peak of mortality after 27 days. After the peaks the hard onset appeared and on December 20 the pandemic dissipated. In the first week the deaths were almost normal, but in the week of 21/10 the Spanish flu raised. From 18/11 to 24/11the flu was 81% of all deaths. The deaths occurred equally for males and females. The Europeans immigrant’s deaths are 23% of all death, for the city they are in 1910 21% of the population.

KEY WORDS: spanish influenza; mortality; morbidity