The International Trade Commission (ITC) and Federal District Courts are two primary forums for the majority of US patent suits. In general, patent holders may choose District Court as a litigation forum, as it can issue damage awards and its requirement is lower than the ITC. However, more and more patent holders seek ITC as a litigation forum as the ITC is a pro-patent holder forum with speedy proceedings and a strong remedy of exclusion order. In order to have a full understanding of US patent litigation, this study analyzes cases from the head of upstream IC design firm, Mediatek, and the head of downstream electronic assembly firm, Foxconn, in District Court and the ITC. Examining from both cases demonstrates there are different situations for upstream and downstream firms. The upstream firms may easily involve clients in suits; while downstream firms are often involved in suits by infringing products from its suppliers or clients. Despite the fact that a majority of Taiwanese high-tech firms were defendants in US patent litigation, both Foxconn and Mediatek cases demonstrate that if they could fight, they would never hesitate to engage in litigation or even proactively bring a lawsuit against infringers. This study reveals a transition from defendant to plaintiff in Taiwanese high-tech firms. In the end, this study provides the litigation strategies for patent holders in forum selection, and accused infringers in arguments and defenses based on the analysis derived from Foxconn and Mediatek cases.