The research was carried out in ten Seed Analysis Laboratories, located in the state of São Paulo, Brazil, using 10 commercial guinea grass seed lots. The work was carried out by only one analyst in alI laboratories, using the same standardized methodology and the same equipment used in the routine of analysis in each laboratory. The objective was to test if the methodology standardization would led to the homogeneization of results. Although there was a tendency to a reduction of the variation coefficients of the laboratories results within seed lots, they were far way of being homogeneous.