The purpose of this project was to implement the MIX Assembly Language, MIXAL, as described by Donald E. Knuth in Fundamental Algorithms, Vol. I, using the macro capabilities of the IBM System/360 Assembly Language. The motivation for implementing MIX was to enable the programmer to write meaningful programs using the MIX Assembly Language regardless of the machine he is actually using. Thus, the programmer would be able to write MIXAL programs even though he does not have a MIX computer on which to run them. The solution to the problem was to build a set of macro instructions that would simulate the various MIX instructions and in turn would form a source statement library. Extensive use was made of conditional assembly instructions. These instructions allow the programmer to vary the sequence of statements generated in a macro instruction. The minimum prerequisite for anyone attempting to write MIXAL programs is a first course in computer science. Inasmuch as the implementation of MIX was accomplished using IBM System/360 Assembly Language, to gain a complete understanding of this project, the reader should have a firm background in System/360 Assembly Language. The implementation of MIXAL has enabled the programmer, who has access to an IBM System/360, to write programs in the MIX Assembly Language. In conclusion, nearly all of the features of Knuth's description of MIX have been implemented in this project. In mentioning restrictions, an attempt was made to indicate how the implementation could be accomplished. Continued work is being performed on the few exceptions that remain.