An experimental investigation into the structural response of cold-formed steel-timber composite flooring systems with innovative and irregularly spaced shear connectors is presented in this paper. Five composite beam tests and a series of supporting material and push-out tests were carried out. The obtained results showed that the innovative shear connectors enabled the generation of considerable composite action, resulting in up to about 45 % increases in load-carrying capacity and 15 % and 20 % increases in the initial and mid-range stiffnesses respectively over the non-composite system. Methods for predicting the effective flexural stiffness and moment capacity of the examined cold-formed steel-timber composite beams are presented and validated against the derived physical test data. It is shown that accurate predictions for both the flexural stiffness and moment capacity can be obtained, with mean prediction-to-test ratios of 0.93 and 0.91 respectively.