Steady increases in the cost of medical care, coupled with a rise in the fraction of workers who lack medical insurance, create incentives for workers who are injured off-the-job to file Workers' Compensation claims. Many analysts have interpreted the high rate of Monday injuries—especially hard-to-monitor injuries like back strains—as evidence of such claims. The analysis in this paper, however, which uses data on “first reports” of injuries filed with the Minnesota Department of Labor and Industry between 1985 and 1989, indicates that workers with low probabilities of medical coverage are no more likely to report a Monday injury than are other workers. Moreover, employers are no more likely to challenge the Monday injury claims of workers with low medical coverage rates than the claims filed by workers with high coverage rates.