Author Abstract: Background. Detection methods for GMO events are required because of regulatory compliance requirements. Efficient detection and quantification of GMO events saves time and resources. Multiplex digital PCR (dPCR) allows detection and quantification of more than one GMO event at the same time. Objective. The study used two tetraplex droplet digital PCR (ddPCR) assays for the detection of 19 soybean GMO events. Methods. Two multiplex dPCR assays were developed and optimized for the detection of 19 soybean GMO events. The first tetraplex ddPCR assay contained four element-specific targets commonly found in GMO plants (P-35S, T-nos, tE9, and Pat). The second event-specific tetraplex ddPCR assay targeted four soybean GMO events that are not detected with the element-specific tetraplex ddPCR (CV127, DP305423, MON87701, and MON87751). Results. The element-specific tetraplex ddPCR assay detected all the expected 15 soybean GMO events. The element-specific tetraplex ddPCR assay also detected selected soybean GMO events at the 0.01% level. The event-specific tetraplex ddPCR assay was successfully used to quantify the four soybean GMO events at the 0.1, 1, 2, and 5% levels. The event-specific tetraplex ddPCR assay also detected the four soybean GMO events at the 0.01% level. Conclusions. The two tetraplex ddPCR assays can be used for the detection of 19 soybean GMO events. Highlights. An element-specific tetraplex ddPCR assay was used to detect 15 soybean GMO events, and an event-specific tetraplex ddPCR assay was used to detect and quantify four soybean GMO events that are not detected by the element-specific ddPCR assay.