The epidemiological importance of some ticks of the genus Ixodes has already been proved. Necessity of a better knowledge of their morphology has led us to undertake a scanning electron microscope (S.E.M.) study of Ixodes ticks in Switzerland, in order to be able to accurately identify the species independent of the development stage examined. I. ricinus, I. apronophorus, I. trianguliceps, I. hexagonus, I. canisuga, I. rugicollis, I. arboricola, I. lividus and I. vespertilionis have been studied. Most of these tick specimens were from the collection AESCHLIMANN deposited at the Lausanne Zoological Museum. The main morphological features are illustrated by micrographs, and results presented in determination keys.