This review covers the key components of calcium handling in cardiac ventricular myocytes. Specifically, L–type current, ryanodine receptors, the diadic space, SERCA pump uptake into sarcoplasmic reticulum, sodium–calcium exchangers, and calciumbinding proteins are reviewed with special focus on attempts to mathematically model these entities. In addition to purely single entities, the review covers other models that have attempted to capture the highly interactive and complex Ca signalling resulting from the interplay of the key components above. These integrative models range in level from microscopic domains to whole cells including electrophysiological mechanisms. In many cases, the differences in competing models reflect the controversies and uncertainties about the underlying biophysical mechanisms. Ultimately, each level of modelling, along with experimental work, will be needed to help elucidate the cellular physiology of this fundamental cardiac signalling system.