Objective To determine the normal value range of glomerular diameter in Chinese adults and to investigate the measurement methods.Methods One hundred patients with minor glomerular abnormalities or thin basement membrane nephropathy diagnosed by renal biopsies from 1998 to 2008 with normal body weight and serum glucose were selected for the determination of normal value range of glomerualar diameter.The maximal profile diameter of glomerualr capillary loops wag measured by Motic Med 6.0 image analysis system in the following ways: (1) direct measurement:two perpendicular longest diameters of each glomerulus were measured.(2) indirect measurement:the area of each glomerular capillary loop was measured,then its diameter Was calculated by formula.Ten patients with minimal change disease,10 with focal segmental glomerulosclerosis,and 10 with membranous nephropathy,who all had normal body weight and serum glucose,were also selected for the measurement of glomerular diameter,whose results were then compared with normal values.Results The results obtained from the direct and indirect measurements were not significantly different.The gender and age had no significant effects on glomerular size.The normal value ranges of glomerular maximal profile diameter were as follows:(1) the glomeruli with pole (s) which maximal profiles were with vascular pole and/or urinary pole:the diameter range measured by the direct method was 101.3-182.9 μm,and by the indirect method was 100.3-181.5 μm.(2) the glomeruli with pole (s) and the glumeruli without pole which maximal profiles were without vascular pole or urinary pole,but were bigger than those in smallest glomeruli with pole (s):the diameter range measured by the direct method was 108.5-182.9 μm,and by the indirect method was 107.6-183.2 μm.In addition,the glomerular maximal profile diameters of 30 patients with glomerular diseases were all in the normal value range.Conclusions Direct and indirect measurement methods are both available.The normal value range of glomerular diameter obtained from this study may be used for Chinese adults.