With the development of tobacco product regulation, knowledge of stability and storage conditions for tobacco products becomes increasingly important. An accelerated aging study is a useful method for stability assessments. It can also reflect additional effects, such as the handling and transportation of smokeless tobacco products (STPs). In this study, 5 different storage conditions, including -22 °C (77% RH), 22 °C (60% RH), 37 °C (70% RH), 42 °C (72% RH), and 60 °C (75% RH), were set up for an accelerated aging study of four certified reference STPs, including loose-leaf chewing tobacco (3S1), snus (1S5), Swedish-style snus (1S4), and moist snuff (3S3). These four reference STPs were manufactured by the Center for Tobacco Reference Products (CTRP) of the University of Kentucky in 2016, under a Cooperative Agreement with the FDA. In this study, six time-points for sample collection were set up, including 3, 7, 14, 21, 28, and 35 days. The analytes tested included pH, nicotine, free nicotine, nornicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N’-Nitrosonornicotine (NNN), and benzo[a]pyrene (B[a]P). Based on our data, pH and nicotine concentration changed most when storage temperature increased. The pH dropped as soon as 3 days at high temperatures and decreased more with time, resulting in significant decreased in free nicotine concentration. Stored for 35 days under the condition of 60 °C (75% RH), total nicotine contents of 1S5, 3S1, 3S3, and 1S4 decreased by 26.1%, 17.3%, 13.5%, and 4.9%, respectively, compared to those stored under -20 °C. This indicated these STPs would lose large amounts of total nicotine if stored or transported at a relatively high temperature.