A new and simple electrospinning method has been developed for producing aligned helical polymer nanofibers. Aligned helical polycaprolactone (PCC) nanofibers were prepared by this method. The helical fibers were collected by a tilted glass slide. The morphology and loop diameters of the helical structures are dependant on the PCL solution concentration and the loop diameters are in the range of 6.9-14.9 mu m for the concentration range of 4.7%-10%. The three-dimensional helical structures were obtained at the high solution concentration of 10%. These helical structures were formed by jet buckling due to mechanical instability when hitting collector surface. Formation of the helical structures is dependent on the obliquity of the tilted glass slide and distance away from the syringe needle. The converging electrical field generated by a tip collector plays an important role in the alignment of the helical structures. (C) 2008 Elsevier Ltd. All rights reserved.