  We discuss a method to constrain the intrinsic three-dimensionale shapes of
galaxy clusters by combining X-Ray and Sunyaev-Zeldovich observations. The
method is applied to a sample of 25 X-Ray selected clusters, with measured
Sunyaev-Zeldovich temperature decrements. The sample turns out to be slightly
biased, with strongly elongated clusters preferentially aligned along the line
of sight. This result demonstrates that X-Ray selected cluster samples may be
affected by morphological and orientation effects even if a relatively high
threshold signal-to-noise ratio is used to select the sample. A large majority
of the clusters in our sample exhibit a marked triaxial structure, with
prolate-like shapes being slightly more likely than oblate-like ones; the
spherical hypothesis is strongly rejected for most sample members. Cooling flow
clusters do not show preferentially regular morphologies.
