A process for manufacturing knitwear, hosiery textile items or seamless items with variable compression on circular weft knitting machines, comprising the steps of activating a program for manufacturing a textile (6); manufacturing a textile item (6); and changing the tension of an elastic yarn (9) fed to the needles (4) by a first feeding device (8) of a predefined value of variation and for a predefined number of times, corresponding to at least two times within the same knitting row during the production of the textile, so as to define in said knitting row of the textile a corresponding predefined number of distinct knitting row portions having a differentiated yarn tension, corresponding to at least two portions of the same knitting row; the step of changing the tension of such a yarn being performed independently from the knitted structure produced and also independently from a variation in the position of the stitch adjusting cams (7).