The factors in woven fabrics that affect the transverse slippage in the sewing process of two-ply fabrics were investigated by discriminant analysis; the seam specimens used were classified into two or three groups on the basis of the maximum amount of slippage. The results showed that the weight and the shear rigidity parallel to sewing direction were very influential on transverse slippage; and that the bending rigidity was also contributory to the slippage but not so crucial compared with the two former factors. The principal component analysis of the fabric data such as weight, thickness, bending rigidity and shear rigidity showed that fabrics that caused transverse slippage could be classified on the scatter chart defined by the first two principal axes. The results obtained will be useful in selecting fabrics at the planning stage, and in preventing slippage at the sewing stage.