To assure the quality of methods for serotyping and antimicrobial susceptibility testing among laboratories in WHO Global Salm-Surv, an international collaborative study on serotyping and antimicrobial susceptibility testing of eight Salmonella enterica strains was performed. A total of 44 laboratories in 35 countries participated. For serotyping, 76% of the results were correct. For susceptibility testing, 92% of the results for the eight Salmonella strains were in agreement with the expected results. However, 28% of the performed tests with the E. coli ATCC 25922 reference strain were out of the quality control range specified by NCCLS guidelines.