University of Kentucky, Center of Tobacco Reference Products (CTRP), has provided reference cigarettes for almost 50 years. These reference cigarettes are widely used as control samples in tobacco research including analytical method development and modified risk tobacco product development. In 2014, CTRP obtained a service agreement with the US Food and Drug Administration (FDA) to produce a certified reference cigarette. The first certified reference cigarette, 1R6F, was manufactured in March, 2015. However, there are no data showing the stability of 1R6F during long-term storage. The objective of this project is to study the stability of the cigarette tobacco filler and resulting mainstream cigarette smoke of 1R6F. Cigarettes were stored at -20 °C, 4 °C and room temperature (~22 °C) for 1, 2, 3, 6, 9 and 12 months. Before they were analyzed, cigarettes stored in -20 °C were transferred to 4 °C for 24hr then room temperature for at least 2hr. The reference cigarettes were conditioned for 48hr at 22 °C and 60% relative humidity, prior to analysis in tobacco filler and mainstream cigarette smoke. Filler analysis included oven volatiles, alkaloids and TSNAs. Smoke analysis included the measurement of alkaloids, TSNAs, CO and TPM under ISO smoking regime. There were no significant changes for the oven volatiles, nicotine and NNN in the filler at 4 °C and -20 °C conditions. However, oven volatiles decreased significantly when cigarettes were stored at room temperature. There were no significant changes for puff/cigarette, CO, TPM, alkaloids and TSNAs in mainstream smoke of cigarettes under -20 °C, 4 °C and room temperature conditions. Our experimental data demonstrated 1R6F cigarettes were stable after one-year storage at 4 °C and -20 °C for selected constituents. This study will continue to monitor the stability of the 1R6F cigarette supply for the duration of this research project.