Distillers Dried Grains with Solubles (DDGS) is widely recognized as a highly nutritious animal feed ingredient. With the exponential growth of the fuel ethanol industry in the past several years, significant quantities of distillers grains are now being produced. To effectively utilize these feeds in the domestic market, these coproduct streams have to be transported greater distances, and must be stored in various structures until final use. Unfortunately, DDGS flow is often problematic, as it frequently becomes restricted by caking and bridging during storage and transport. This issue may arise from a number of factors, including storage moisture, temperature, relative humidity, particle size, time, or temperature variations. The objective of this study was to examine the effect of various moisture content levels (10%, 15%, 20%, 25%, and 30% d.b.) and calcium carbonate (a common flow agent) levels (0%, 1%, and 2% w.b.) on the resulting physical and flow properties (Carr indices) of DDGS with varying soluble levels (10%, 15%, 20%, and 25% d.b.). The results showed that DDGS flowability declined with increased soluble and moisture content levels. Flow agent (CaCO3) addition did not have a significant effect in improving the flow properties of DDGS. This may have been due to no surface affinity between DDGS and the flow agent particles, or too little inclusion of the flow agent.