Ready-to-use colorimetric substrate for caspase-1/ICE and related caspases that recognize the amino acid sequence YVAD. Caspase-1 and related caspase activity can be quantified by spectrophotometric detection of free pNA (l= 400 nm) after cleavage from the peptide substrate YVAD-pNA, using a spectrophotometer or multi-well plate reader. The ready-to-use caspase substrate provides an economic alternative for large volume users.