Mean Optical Density (M.O.D.) determination of six G-bands on X-chromosomes was performed on 45 patients with Turner's syndrome and compared with X-chromosomes from women controls with a normal karyotype by a Chromosome Image Analysis System. Density profiles were constructed to obtain standard values for the staining intensity and frequency of occurrence of chromosome bands. Statistical analysis showed that the M.O.D. were significantly different for Xq12, Xq21, Xq25 and Xq27 G-bands between the Turner and Control groups. Most within-group differences were small and appeared not to be statistically significant.