In order to investigate the interrelationship amongst grain size, cell size, cell wall thickness and flow stress in type 316L stainless steel, tensile specimens of grain sizes 3.1-86.7 μm were deformed to a strain of 0.34 at the temperatures 297, 673 and 973 K and at a strain rate 1 × 10-4 s-1. The cell wall thickness is found to be larger than the cell interior size but the two are mutually related and only marginally decrease with the increase in grain size. The difference in the distributions of dislocations and cell structure in the vicinity of grain boundaries and in the grain interior leads to a variation in their relative contributions to strengthening. The smaller cell interior sizes and thicker cell walls result in a greater contribution of grain interior to strengthening of polycrystalline material than the grain boundaries, with the maximum effect observed at 673 K due to dynamic strain aging. © 2002 Acta Materialia Inc. Published by Elsevier Science Ltd Inc. All rights reserved.