Serine⁄threonine kinase 33 (STK33⁄Stk33) is a recently discovered gene whose inferred amino acid sequence translation displays characters typical for a calcium⁄calmodulin dependent kinase (CAMK). In this study we ana-lysed the STK33⁄Stk33RNA and protein distribution and the localization of the protein. TheSTK33⁄Stk33expression pattern resembles those of some related members of the CAMK ⁄Stk33displays a non-ubiquitous and, in most tissues, low level of expression.