AbstractSamples of two helically wound monofilaments were used as experimental models to check the theoretical expression for light scattering from helixes. A method of estimating the pitch and tilt of the helixes was outlined and the results were compared with measurements from microscopy. The agreement was satisfactory. Layer line streaking and splitting was observed and explained in terms of irregularity of the helical parameters. Samples of several helically wound monofilaments were also prepared and their scattering patterns were compared with those from native and regenerated cellulosic fibers.