This report summarizes 2007 West Nile virus (WNV) surveillance data reported to CDC through ArboNET as of 3 a.m. Mountain Daylight Time, September 11, 2007. A total of 38 states have reported 1,395 cases of human WNV illness to CDC. A total of 770 (56%) cases for which such data were available occurred in males; median age of patients was 49 years (range: 15 months-96 years). Dates of illness onset ranged from January 8 to September 7; a total of 38 cases were fatal.