Femicide has received relatively little research attention, despite its severity. Estimates of femicide depend on the strategies used to define it within the sociocultural and political context. This study aimed to assess intentional homicides of women, focusing on femicides, highlighting the characteristics and risk factors. This was a cross-sectional study based on daily surveillance of homicides in the press and mortality records. The study considered fatal victims of assault in women over 11 years of age in Manaus, Amazonas State, Brazil, in 2016-2017. Classification of femicide was based on Brazil's Law n. 13,104/2015. Relative risk was estimated by Poisson regression, and a hierarchical model was used to include variables in the models. Analyses were performed in the R statistical package. Of 138 fatal victims of assault, 52 were cases of femicide, or 37.7% (CI: 29.4-45.5). Each unit addition of age reduced the risk of femicide by 3% (CI: 0.95-0.99). Risk of femicide was 40% lower (CI: 0.40-0.90) in women with up to seven years of schooling, when compared to those with eight years or more. Women killed by bodily force showed 5.5 times higher risk (CI: 2.6-11.3) of femicide, compared to those killed with firearms. Relative risk of femicide was 1.4 (CI: 1.1-2.7) in women killed in daytime, compared to those killed at night. The proportion of femicide in this study was lower than in previous estimates in Brazil, and the local burden of urban crime appears to explain part of this discrepancy. This study showed that age, schooling, use of bodily force, and time of day when the assault occurred are associated with femicide.