  We study consequences of custodial symmetry in the Higgs sector of the
Georgi-Machacek (GM) model. We discuss how the 5-plet and 3-plet Higgs bosons
classified under the custodial SU(2) symmetry are produced and decay at the
CERN Large Hadron Collider. By determining their masses through proposed
channels, we can test the mass degeneracy in each Higgs multiplet.
