ions for Petri Nets and Other models of Concurrency (APNOC) organized by Alexander Serebrenik and Natalia Sidorova, Scalable and Usable Model checking for Petri nets and other models of concurrency (SUMo) organized by Didier Buchs, Fabrice Kordon, Yann Thierry-Mieg, and Jeremy Sproston All these workshops have been organised as a discussion platform for researchers interested in the application of Petri nets and other formal concurrency models in many current elds of study, namely in biology, synthesis, software engineering, and model checking. Independent reviewers have carefully reviewed all papers. For more details, please see the PETRI NETS / ACSD 2010 website: http://acsd-petrinets2010.di.uminho.pt January 2012