Third Workshop on Data Mining for Healthcare Management

Held in conjunction with
The 16th Pacific-Asia Conference on Knowledge Discovery and Data Mining
May 29th - Jun 01st - Kuala Lumpur, Malaysia

Here are some links to publicly available datasets:

UCI Machine Learning Repository
KDD Cup 2008 -Siemens (Requires registration)
MIT-BIH Arrhythmia Database
ECML/PKDD discovery challenge dataset.
Patients admitted to Chiba Hospital in Japan from the period 1982 - 2001. This data was released in 2004 as ECML/PKDD discovery challenge.

In the left side panel menu, you can register and then download the data. Also to get quick answers for some of the initial questions that you may have about the data, I think it is worthwhile to quickly browse through the data description and FAQs given for each data set.
Healthcare Cost and Utilization Project (H-CUP)
HIV Prevention Trials Network - Vaccine Preparedness Study/Uninfected Protocol Cohort
National Trauma Data Bank (NTDB)
Behavioral Risk Factor Surveillance System (BRFSS)
Link to National Public Health Data Sets

For any further questions please contact Prasanna at prasanna [at] gmail [dot] com