Codes for Euclidean channels are discussed in this chapter. In case of Euclidean channels the input codewords are usually arbitrary members of the n-dimensional Euclidean space ⁿ. However, by energy constraint reasons the code-words are assumed to have Euclidean norm: one at most. This way they are closely related to spherical codes and “kissing numbers”. In addition to this some other constraints are assumed, usually with respect to the Euclidean distance of code-words or groups of codewords. Here we shall discuss the best known bounds and constructions for multiple access Euclidean channels.