The R package Combinitorially Complex Equilibrium Model Selection (ccems) performs model selections of equilibriums in general and quasi-equilibriums of enzyme complexes in particular. Estimates of dissociation constants K that best describe a dataset are found by systematically scanning through possibilities of K being infinity and/or plausibly equal to other K. The automatically generated models are then fitted to data. Automation enables searches of spaces too large to be specified by hand, e.g. spaces generated by combinatorially complex equilibriums. Current limitations are to 2-reactant systems, average protein mass data or enzyme reaction rate data, and systems where total reactant concentrations are approximately known exactly (i.e. reconstituted from purified reactants). ccems is available as a binary zip file for windows and as a source tarball for linux ccems_1.05.tar.gz. Package use in windows is limited to learning from interactive pilot sessions. The intended use of this package is on a ROCKS cluster.