A yarn strength correlation analysis for the 22/1 yarn spun through a Miniature Spinning Plant (X) and the yarn of same count spun through an industrial equipment (Y) was carried out for 81 pairs of observations. The correlation coeficient between the two processes showed to be r = 0.563 **. The regression equation is of the form: Y = 611.631 + 0.486X. It was showed that the equations to predicted yarn strength, calculated for 9 pairs of values in each location, give better estimations than the general equation calculated for 81 pairs in 9 locations. The highest correlation coefficient (r = 0.944 **) was found for the locality of Campinas.