To critically assess the method of capillary electrophoresis (CE) we examined 1000 prospective serum samples submitted for protein electrophoresis by both high-resolution agarose gel electrophoresis (HRAGE) and CE. CE was performed using a 72 cm (50 cm to detector) x 50 microns I.D. fused-silica capillary with detection of absorbance at 200 nm. The 1000 samples examined contained 362 monoclonal paraproteins with concentrations ranging from 1 to 71 g/l. We evaluated the individual paraprotein correlations, the overall correlation between the two methods being 0.96. We found that HRAGE gave slightly higher values for the monoclonal bands than CE and the difference was statistically significant. We conclude that CE is a viable alternative to HRAGE for the determination of protein dyscrasias in a routine clinical laboratory.