  We study formal deformations of multiplication in an operad. This closely
resembles Gerstenhaber's deformation theory for associative algebras. However,
this applies to various algebras of Loday-type and their twisted analogs. We
explicitly describe the cohomology of these algebras with coefficients in a
representation. Finally, deformation of morphisms between algebras of the same
Loday-type is also considered.
