Occupational solvent exposure may increase the risk of connective tissue disease (CTD). The objective of this case-control study was to investigate the relation between undifferentiated connective tissue disease (UCTD) and solvent exposure in Michigan and Ohio. Women were considered to have UCTD if they did not meet the American College of Rheumatology classification criteria for any CTD but had at least two documented signs, symptoms, or laboratory abnormalities suggestive of a CTD. Detailed information on solvent exposure was ascertained from 205 cases, diagnosed between 1980 and 1992, and 2,095 population-based controls. Age-adjusted odds ratios (OR) and 95 percent confidence intervals (CI) were calculated for all exposures. Among 16 self-reported occupational activities with potential solvent exposure, furniture refinishing (OR = 9.73, 95 percent CI 1.48-63.90), perfume, cosmetic, or drug manufacturing (OR = 7.71, 95 percent CI 2.24-26.56), rubber product manufacturing (OR = 4.70, 95 percent CI 1.75-12.61), work in a medical diagnostic or pathology laboratory (OR = 4.52, 95 percent CI 2.27-8.97), and painting or paint manufacturing (OR = 2.87, 95 percent CI 1.06-7.76) were significantly associated with UCTD. After expert review of self-reported exposure to ten specific solvents, paint thinners or removers (OR = 2.73, 95 percent CI 1.80-4.16) and mineral spirits (OR = 1.81, 95 percent CI 1.09-3.02) were associated with UCTD. These results suggest that exposure to petroleum distillates increases the risk of developing UCTD.