Dalea formosa Torr. (feather dalea, featherplume) was collected from the Jornada Experimental Range in south central New Mexico. Current year's growth was collected from 10 plants, all found within an approximate 50 m radius of the GPS coordinates N32o40.645' and W106o33.601' during July 2001. Composite samples of the plants were steam-distilled in triplicate, and the essential oil was analyzed using both GC-FID and GC/MS. To explore the possibility of using solid-phase microextraction (SPME) in place of steam distillation, compositions of plants collected from the same site were also examined using SPME. Mass spectra and retention indices were used to identify 58 previously described compounds. The retention index and EI mass spectra are provided for one unknown. Alpha-pinene (31.7%), camphene (8.4%), and limonene (8.1%) were the major constituents of the oil. Beta-pinene made up only 5.8% of the oil but accounted for 13.2% of the SPME chromatogram peak area. This difference in composition may be du to either sampling technique or harvesting time.