The current status of the Proficiency Analytical Testing (PAT) program was discussed. The PAT program was a cooperative venture of NIOSH and the American Industrial Hygiene Association in which quality control reference samples were sent to over 1400 occupational health and environmental laboratories in 15 countries. The samples consisted of three metals, quartz (14808607), organic solvents, and either amosite (12172735) or chrysotile (12001295). The samples were mailed to the participating laboratories each calendar quarter (designated a round). The performance of the participating laboratories was evaluated by comparing their reported results against an acceptable performance limit established by reference laboratories. Results of the current PAT round, round 111 in October 1992, were discussed. A total of 1446 laboratories participated in this round. The samples consisted of cadmium (7440439), lead (7439921), zinc (7440666), quartz, chrysotile, carbon-tetrachloride (56235), 1,2-dichloroethane (107062), and trichloroethylene (79016). More that 90% of the laboratories were rated as proficient.