Contains papers from two workshops: BioConcur 2004 held in London, UK in August 2004 and BioConcur 2005 held in San Francisco, CA, USA in August 2005. This work contains 8 papers that deal with various aspects of computational methods, algorithms and techniques in bioinformatics.

Modelling the Influence of RKIP on the ERK Signalling Pathway Using the Stochastic Process Algebra PEPA.- Gene Regulation in the Pi Calculus: Simulating Cooperativity at the Lambda Switch.- From Logical Regulatory Graphs to Standard Petri Nets: Dynamical Roles and Functionality of Feedback Circuits.- Translating SBML Models into the Stochastic ?-Calculus for Stochastic Simulation.- Graph Theory for Rule-Based Modeling of Biochemical Networks.- Adapting Biochemical Kripke Structures for Distributed Model Checking.- A Graphical Representation for Biological Processes in the Stochastic pi-Calculus.- On Differentiation and Homeostatic Behaviours of Boolean Dynamical Systems.- A Specification Language and a Framework for the Execution of Composite Models in Systems Biology.- A Specification Language and a Framework for the Execution of Composite Models in Systems Biology.