We propose aggregation indices of Non-Tariff Measures (NTMs) to quantify their protectionism relative to international standards. We apply the indices to national Maximum Residue Limit (MRL) regulations affecting agricultural and food trade and using a science-based criteria embodied in Codex Alimentarius international standards. The approach links two streams of the NTM literature, one concerned with the aggregation of various NTMs into operational indices for econometric and modeling purposes, and the other attempting to evaluate the protectionism of NTMs. The data used in the application come from a large international dataset on veterinary and pesticide MRLs and CODEX MRL standards for a large set of countries.