Isotactic poly(acrylonitrile) (PAN) has been prepared by means of a conventional ultraviolet (UV) irradiation apparatus without gamma-ray sources; an acrylonitrile-urea canal complex was directly formed at the surface of the UV (Hg) emission tube at low temperatures (similar to -78 degrees C). When the complex was UV-irradiated at this temperature, a stereoregular polymer was formed in the canal. The C-13-NMR analyses indicate that (1) these PAN are rich in isotactic configuration, (2) the extent of the isotactic triad is in the range of 56-71%, and (3) the penultimate unit effect, 4 (mm) (rr)/(mr)(2), is linearly correlated with the ultimate unit effect, (mm)/(rr). From the plots of log {4(mm)(rr)/(mr)(2)} vs log {(mm)/(rr)}, the anomaly in the polymerization of AN is discussed. The molecular characteristics of the UV canal PAN such as molecular weight, etc., were briefly noted.