Edible snails are kept in farms in many countries worldwide. As farm animals, they are an object of interest of veterinary studies and applied biology. There is a large demand for tests which would help identify their health and well-being. The objective of this study was to assess the usefulness of determining the concentration of urea in hemolymph as a marker of health of the Lissachatina fulica and Cornu aspersum edible snails. The observation covered snails from four farms marked from A to D, in which numerous deaths (farm A) and decreased body weight gain (farms B and C) were observed. In experimental farm D we observed a group of snails subjected to stress and a control group maintained in correct conditions. High concentrations of urea were found in the hemolymph of all farm animals from farms A, B and C, as well as in those subjected to food deprivation in farm D (on average from 96 mg/dl in farm D to 320 mg/dl in farm A). On the other hand, in controls from group D, the concentration of the parameter in question was much lower (< 2.0 mg/dl). The results obtained indicate that the urea concentration is a non-specific marker of pathological conditions in snails, and that the continuous monitoring of this parameter makes it possible to demonstrate irregularities in farming and introduce appro- priate and early measures to eliminate such disturbances.