The objective of the present study was to examine the possibility of using a viscoelastic (free) solution to separate DNA molecules. The electrophoretic orientation of lambda DNA in an uncross-linked polyacrylamide solution was measured by a fluorescence-detected linear dichroism of bound ethidium bromide. The lambda DNA molecules oriented almost parallel to the applied electric field direction during electrophoresis in a relatively low concentration of the polyacrylamide solution for a moderate electric field strength of 90 V/cm, and the extent of orientation increased with the field strength. The analogy between the DNA molecule and a thin cylindrical body in the polyacrylamide solution suggests that when one perfects the separation device, very large DNA molecules can be separated using a viscoelastic solution.