In 2013 the CORESTA Smokeless Tobacco Sub-Group (STS) conducted a collaborative study with the aim of expanding the scope of the CORESTA Recommended Method (CRM) No. 73, Determination of Ammonia in Tobacco by Ion Chromatographic Analysis, to include smokeless tobacco products. This report explains the work done to calculate repeatability and reproducibility (r&R) values and determine if the methodology was suitable for the determination of ammonia in tobacco and smokeless tobacco products.