The structure of the title compound, [Ca(C(10)H(15)O(4)S)(2)(H(2)O)(4)], is the first example in which two D-camphor-10-sulfonate anions are coordinated to a metal ion, in this case with direct Ca-O bonding. The molecule has crystallographically imposed twofold symmetry with the Ca atom on the twofold axis. Hydrogen bonds are formed between the coordinated water molecules and the O atoms of the SO(3)(-) groups of adjacent molecules, leading to the formation of a two-dimensional layered network. The compound displays sharp wavelength-selective transparency in the UV-visible spectrum, offering the potential for application as an optical filter.