Lis pendens is one of the negative procedural assumptions, or obstacles to the conduct of proceedings, the existence of which prevents the conduct of litigation and the adoption of meritorious decisions. While the proceeding is ongoing, a new proceeding cannot be initiated between the same parties regarding the same cause of action, and if such is initiated, any court other than the court first seised shall decline jurisdiction in favour of that court. The problem of parallel proceedings also exists in international civil procedural law and is governed by the rules of the rules of the Brussels I. bis Regulation, which is binding and directly applicable to all Member States. Very strict application of the rules on lis pendens before the adoption of the Brussels I. bis Regulation endangered the autonomy of the parties, because these rules prevented the application of the agreement on the choice of court, which was the main reason for the adoption of the new rules on lis pendens in Brussels I. bis Regulation. The new rules should provide priority to the application of the agreement on the choice of court concluded by the parties. The changes to the rules on lis pendens from the Brussels Convention, through Brussels I. Regulation, to the latest changes introduced by Brussels I. bis Regulation are presented, the rules on lis pendens and their connection with the rules on the agreement on the choice of court are analyzed, as well as the problem of parallel proceedings and related actions in third States.