Droplet spectra data were collected from spray equipment intended for use in vector control by the U.S. Department of Defense pest management programs to determine if they produce droplets in the ultralow volume (ULV) spectrum. Droplets generated by 26 sprayers utilizing water+nonionic surfactant (NIS) and/or BVA-13 mineral oil were measured at various operating conditions resulting in a total of 360 replicated tests. The volume median diameter (D-V0:5) of the application equipment ranged from 3.5 to 215.3 mu m. Ten of all the sprayers tested with water+NIS and 15 of all those tested with BVA-13 mineral oil produced ULV sprays. All thermal foggers tested met the criteria for space sprays when applying mineral oil but not when applying water. Generally, droplet size increased with increased flow rate, resulting in some of the sprayers generating droplets that were too large (> 50 mu m) to be considered ULV sprayer at the higher flow rates. Also, decreases in engine, blower, fan, or rotary atomizer rpm resulted in increased droplet size. Therefore, careful attention should be given to the application parameters during selection and operation of a sprayer. As a rule of thumb, if the reported data are close to the D-V0:5 and D-V0:9 thresholds for ULV (25 and 50 mu m, respectively), changing any of the operational parameters from those listed here could result in an ineffective application. The data presented serve as a guide for users in selection of sprayers and corresponding operational parameters to meet the specific application requirements.