This book constitutes the thoroughly refereed postproceedings of the Second International Workshop on Active Mining, AM 2003, held in Maebashi, Japan, in October 2003 as a satellite workshop of ISMIS 2003. The 16 revised full papers presented together with 2 tutorial papers and an overview of the Japanese Active Mining Project went through 2 rounds of reviewing and improvement and were selected from initialy 38 submissions. The papers are organized in topical sections on active information collection, active data mining, and active user reaction. Many current aspects of active mining are addressed, ranging from theoretical and methodological topics to algorithms and their applications in fields such as bioinformatics, medicine, and life science more generally.