Presented herein are data that describe collections, expenditures, personnel, and services in 65 medical libraries at Association of Research Libraries (ARL) member institutions throughout North America. In 2005-06, the reporting health sciences libraries held a median of 245,212 volumes, spent a total of $239,944,918, and employed 2,524 FTE staff. Expenditures for materials and staff accounted for the bulk of total expenditures, at 46% and 41% respectively. Respondents reported spending a total of $51,689,469 for electronic materials, or a median of 54.29% of their total materials budgets. This includes a total of $47,179,215 for electronic serials. List of ARL Member Libraries as of June 1, 2007 is appended. (Contains 6 tables.) [For "ARL Academic Health Sciences Library Statistics, 2004-05," see ED498304.]