The molecular weight analysis of urinary proteins can provide useful diagnostic information. For this purpose a routine method of sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-electrophoresis) is described. The main problem in the introduction of this method into the clinical laboratory lies in the availability of "ready-to-use" electrophoresis gels with good and reproducible quality. A device for gel production is therefore described, which is easily constructed from plastic package materials. Polyacrylamide gels are made batch-wise and in advance. They are suitable for various types and techniques of horizontal electrophoresis. Further, a method for analysis of urinary proteins is described, which permits the simultaneous analysis of 22 unconcentrated urine samples within a 3-hour-electrophoresis run. A specially optimized Coomassie blue staining method (overnight) ensures detection of proteins in the concentration range of milligrams per litre. Electrophoretic analyses were documented by photocopying the finished electrophoresis gels.