Caspase-6 has garnered much attention recently since it has been shown that it is involved in the developmental pruning of axons [16, 17] , and it has been suggested that similar pathways might erroneously be activated in neurodegenerative disorders such as Alzheimer's (AD) and Huntington disease (HD) [16, 18] . The presence of activated caspase-6 and cleavage of caspase-6 substrates is indeed a hallmark of AD, HD and cerebral ischemia, and has been shown in a number of different animal models and patient brain tissue [18, 19, 20, 21, 22] . To assess caspase-6 activity in cell and tissue samples, peptide substrates or inhibitors need to be titrated accurately to yield meaningful results, since the peptide substrate commonly used to assess caspase-6 activity, VEID, can be cleaved by other caspases as well as the proteasome when used at too high concentrations [23, 24] . In addition, even low concentrations of a VEID substrate can lead to inaccurate results if the relative amount of other proteolytic activity in the sample is significantly higher than that of caspase-6 due to small differences in kcat/Km [4] . A recently developed method using the biotinylated caspase inhibitor zVAD is significantly more specific, but to achieve this specificity, immunoprecipitation and subsequent detection of the active caspase by Western blotting is required [23] . For a more quantitative way of assessing caspase-6-specific activity, we have developed a novel method based on the cleavage of lamin A [24] . Here we show that this method is sensitive, specific and allows for the detection of caspase-6 activity in complex samples. The assay quantitatively measures caspase-6 activity and can be useful for investigating caspase-6 biology as well as the screening and intracellular efficacy assessment of caspase-6 inhibitors.