Gonçalo Moniz Institute (Fiocruz-BA).Portal hypertension and periportal fibrosis commonly occur in severe Schistosoma mansoni infection. Changes in lipid profile and elevated levels of circulating liver enzymes have also been described in infected individuals. The present study sought to assess the alterations in laboratory parameters associated with liver disorder in individuals infected by S. mansoni who visited a private routine laboratory service. Levels of circulating liver enzymes (gamma-glutamyl transferase [γ-GT], aspartate transaminase [AST], alanine transaminase [ALT], and alkaline phosphatase [ALP]) and a lipid panel (total cholesterol [COL], high-density lipoprotein [HDL], low-density lipoprotein [LDL], very low-density lipoprotein [VLDL], and triglycerides [TRI]) were evaluated in both infected and non-infected individuals and relative risk was used to measure associations. Methods: Data were collected for analysis from a total of 1,078 cases identified in 379,600 individuals who submitted samples to the Datalab Laboratory (Salvador, Bahia) between 2004 and 2008. Results: S. mansoni infection led to increased circulating levels of γ-GT in both women and men, AST (women), and ALP (men). S. mansoni infection was a protective factor against increased levels of TRI, CHO, and VLDL for individuals aged 19 years or older. The results of our analysis indicate that alterations in lipid metabolism and circulating liver enzymes in asymptomatic S. mansoni-infected individuals might be attributed to eggs lodged in the hepatic sinusoids. Conclusions: Parasitological testing for S. mansoni should be indicated in endemic areas when this pattern of alterations is detected.