BACKGROUND: Syphilis constitutes a challenge for national and global public health due to the repercussions on human life. The objective of the study was to characterize the epidemiological profile of the cases of syphilis treated in the health system of zones 6 and 7. METHODS: Cross-sectional study of secondary data collected in the form of investigation / notification of syphilis of all people attended and diagnosed by fluorescent treponemal antibody absorption tests. The inclusion criteria were the clinical and epidemiological data of suspicion for syphilis. The variables analyzed were age, sex, origin, residence and diagnostic tests. Odds Ratio and Chi2 were used for the statistical inference analysis using the Epi info 7.2 programs RESULTS: 72 % of people diagnosed with syphilis are between 20 and 49 years old, 53 % of women. The confirmatory tests were reactive in 75 % of the cases, of which 27 % presented non-reactive serological tests and 77 % without previous tests. The provinces with the highest incidence of cases were Cañar (93 %) and Morona Santiago (87 %). Protective factors were female sex (OR 0.41, 95 % CI 0.25 - 0.68) and residence in the province of Loja (OR 0.21, 95 % CI 0.10 - 0.46) CONCLUSIONS: The prevalence of cases of syphilis is found in the age group of 20 to 49 years andmale. The protective factors identified in a statistically significant manner were female sex and residence in the province of Loja. It is suggested to develop strategies to expand coverage in people with suspected syphilis, to undertake prevention and health promotion programs.