A sample of 206 children (between 1 and 16 years-old) in Huertas (n = 110) and Julcán (n = 96) districts of the Mantaro Valley, Peru, were studied with a clinico-epidemiological interview, serology and fecal parasitologic tests to describe the prevalence and analyze risk factors of infection by Fasciola hepatica (Fh). Fh prevalence by fecal examinations in Huertas (H) was 28.3% and Julcán (J), 12.6%. Using serological tests, the prevalences were: for H, 36.3% and for J, 22.7%. Univariate analysis showed a significant association between Fh infection and 3 variables in H: living near small streams (OR= 4.8; P < 0.05) or farms (OR= 2.88; P < 0.05) and the habit of drinking hot herbal drinks "emolientes" (OR= 2.92; P < 0.05); and in other 3 variables in J: having a single room per house (OR= 21.0; P < 0.05), defecating in the fields (OR= 4.77; P < 0.05), history of taking antiparasitic medication in the last six months (OR= 4.61; P < 0.05). Multivariate analysis, applied to the whole set of data revealed as possible risk factors for infection with Fh: the habit of drinking "emolientes" (OR= 5.16; P < 0.05) and living near small streams (OR= 17.22; P < 0.05) or in farms (OR= 8.13; P < 0.05). According to these results one of the most important and less recognized risk factors is the habit of drinking "emolientes". Due to the clinical importance of human fascioliasis, we conclude that its presence in the Mantaro Valley is an important public health problem, effective early diagnosis would allow rapid treatment and avoidance of the serious impairment brought by chronic infection.