The transition among many US physicians from independent practice to hospital employment has raised concerns about whether employed physicians will be more inclined to refer patients for hospital-based services that are unnecessary or inappropriate. Using claims data for 2009-16, we conducted a difference-in-differences analysis to investigate whether this form of hospital-physician integration is associated with inappropriate referrals for magnetic resonance imaging (MRI), a widely used mode of diagnostic imaging, for three common medical conditions: lower back pain, knee pain, and shoulder pain. Study findings indicate that the odds of a patient receiving an inappropriate MRI referral increased by more than 20 percent after a physician transitioned to hospital employment. Most patients who received an MRI referral by an employed physician obtained the procedure at the hospital where the referring physician was employed. These results point to hospital-physician integration as a potential driver of low-value care.