Euglandinawas collected over a three‐year period in four habitat types in Mauritius. Smaller collections were also made in Reunion and Rodrigues. The areas in which theEuglandinawere collected were simultaneously sampled for potential prey species. Identification of the stomach contents and comparison with the available prey shows that most prey are eaten whole and that native species are eaten in greater numbers that would be expected form a consideration of their numbers in the habital.Achatinaspp., whichEuglandinawas originally introduced to control, was not positively identified in the diet. Even if all unidentified prey fragments were formAchatinathen this would form less than 5% of the total number of items in the stomachs.Habital destruction, together with predation byEuglandina, appear to be major contributors to the extinctions of native Mauritian snails. The conservation of primary forests, into whichEuglandinahas not penetratd, is suggested as the most effective way to save the remaining endemic ground‐dwelling snails form extinction. These results add further emphasis to the importance of preventing introductions ofEuglandinato areas with native snail faunas, and show clearly that this predator is not a successful control agent forAchat