The dramatic increase of direct-to-consumer advertising (DTCA) of prescription drugs created intensive debates on its effects on patient and doctor behaviors. Combining 1994–2000 DTCA data with the 1995–2000 National Ambulatory Medical Care Surveys, we examine the effect of DTCA on doctor visits. Consistent with the proponents' claim, we find that higher DTCA expenditures are associated with increased doctor visits, especially after the Food and Drug Administration clarified DTCA rules in August 1997. After 1997, every $28 increase in DTCA leads to one drug visit within 12 months. We also find that the market-expanding effect is similar across demographic groups.