Perchlorate was unambiguously detected by ion chromatography-suppressed conductivity (IC-CD) and/or ion chromatography-electrospray mass spectrometry (IC-MS) in seven of seven supermarket milk samples bought randomly in Lubbock, TX. Quantitation by IC-MS and IC-suppressed conductivity detection in conjunction with a preconcentration-preelution method provided comparable results. With a sample cleanup procedure that involved protein removal by ethanol and sequential passage though activated alumina and C-18 silica, the limit of detection for perchlorate in milk was 0.5 microg/L. The levels found ranged from 1.7 to 6.4 microg/L. An evaporated milk sample contained perchlorate at 1.1 +/- 0.6 microg/L level, while we did not find detectable levels in a reconstituted powdered milk sample.