By using high resolution two-dimensional (2D) gel electrophoresis coupled with computer-analysis we have established a quantitative Drosophila wing imaginal disc protein database of third instar larvae as a reference to be used for comparative purposes in genetic studies. A general catalogue integrated by 1,184 (35)S-methionine-labelled polypeptides from wing imaginal disc has been obtained. The level of expression for all the proteins has been quantitatively determined. The quantitative reproducibility of the analysis system has been estimated and all the controls studied as database reference to interpret the results of experiments with mutant discs. One example, corresponding to iro (1) mutation, has been used to show how some of the changes observed with mutant discs clearly extend out of the limits defined by the controls. This enables us to generate comparative parameters for the study of proliferation, morphogenesis and differentiation of Drosophila and opens the possibility of rapidly defining the nature and quantity of changes in patterns of gene expression in developmental genetic studies.