This paper presents and discusses a large number of gas separation membrane cascade schemes using two compressors. Although some of these cascade schemes are known in the literature, the majority are new, providing more options for a given separation task. Broad guidelines an presented on the suitability of the various cascade schemes based on the degree of enrichment of each product stream. It is shown, through an example, that for certain applications when the feed is at a low pressure, a suitable scheme from the suggested array of two-compressor cascade schemes can provide a better solution in terms of power and membrane area than for the already known case where either only one compressor is used or the feed is first compressed and one recycle compressor is used.