The extinction efficiency is calculated for a volume containing randomly oriented long circular cylinders. The results are compared with the extinction efficiency of spheres with the same refractive index and are shown to be almost identical. Special attention is given to a corrected definition of the extinction efficiency for obliquely oriented cylinders with respect to the incident radiation direction. The corrected definition presented here is justified by use of the physical concept of the extinction efficiency as used in the case of other scatterers such as spheres. Calculations are presented for a polarized incident light (normal to the incident plane) when discussing the definition of the extinction efficiency. For the randomly oriented particles the incident light is assumed to be unpolarized.