Abstract: A proportional relationship between pesticide application rate and residue on harvested commodity would imply that residues from field trials with higher or lower application rates could be proportionately adjusted by a corresponding factor. If such a relation can be demonstrated to be independent of crop, pesticide and type of application, then residue data from field trails conducted over a range of application rates could be normalized to label rate values. The background, process and principle on the use of proportionality approach to estimate maximum residue limits(MRLs) for pesticides by Codex Committee on Pesticide Residues (CCPR) were presented. Scaling is only acceptable if the application rate is the only deviation from critical GAP(cGAP). Such a principle would increase the size of the residue database supporting the pesticide MRL.