The lack of a fast selection method to identify the most stable protein is one of the major challenges for developing successful therapeutic protein formulations more rapidly. The swift and accurate detection of small amounts of aggregates is another problem since aggregates may trigger an immunological response and the aggregation decreases the biological activity of the antibody. Here we present an alternative method for initial screening of the aggregation propensity of proteins, using monoclonal antibodies (mAb) as an example and thioflavin T (ThT) binding. The major advantage of ThT binding is the short duration of testing compared with size-exclusion chromatography (SEC) measurements that can take 6 months or more even under accelerated conditions. The tendency to aggregate of each therapeutic human mAb probed with the ThT assay, together with SEC, is employed to formulate the ranking of mAb aggregation. ThT binding can determine the propensity of proteins to aggregate in a few days, illustrating that ThT binding would be a valuable screening tool.