The effect of fiber concentration (nL(3)), fiber length (L), and cylindrical container walls on the static orientation state of a suspension of rod-like particles is examined with computer simulation. The orientation distributions are determined for both confined and unbounded suspensions of otherwise randomly distributed and randomly oriented, non-Brownian, rigid rods. Experimental determination of the distribution of orientations in a suspension confined to a cylindrical vessel is used to validate the results of our computer simulation. For unbounded systems, the simulations are in agreement with theoretical predictions for the concentration at which a departure from isotropic configuration is expected. For systems confined into finite-sized cylinders, the orientation of the rods is not completely isotropic, even when the concentration of particles is very low and the size of the container relatively large (seven times the size of the suspended-rod length). A linear dependence of the anisotropy on the concentration up to the highest concentration examined (nL(3) = 76) is found. Finally, we determine that over a large range of concentrations and rod sizes the effect of solid surfaces and free surfaces is confined to a distance of half rod-length from the bounding surfaces. (C) 2003 The Society of Rheology.