The PIKM 2012 workshop is the 5th of its kind after 4 successful PhD workshops at ACM CIKM. This PhD workshop invites papers that describe the Ph.D. dissertation proposals of doctoral students in any of the CIKM areas: databases, information retrieval, data mining and knowledge management. Interdisciplinary work across these tracks is particularly encouraged. This year PIKM has received around 25 submissions from over 12 countries across the globe, among which 10 have been accepted as full papers for oral presentation while 4 have been accepted as short ones for poster presentation. The selection has been conducted based on reviews submitted by an expert team comprising 21 PC members spanning 12 countries and 6 continents with a good balance of industry and academia.