With an eye on expansion, New York-based medical scheduling site ZocDoc raised a $15 million second round of institutional funding. Founders Fund led the round, with existing investors Khosla Ventures participating.

ZocDoc, which launched in 2007, is basically OpenTable for doctors. The service allows users in New York, San Francisco, Washington, D.C., and Chicago to view doctors’ schedules online and book appointments across 20 different specialties.

Patients can make same day appointments, a vast improvement over the 20 days the average patient waits for an appointment with a primary care physician. It also helps doctors fill the 10 to 20 percent of scheduled appointments that patients cancel each year, according to company statistics.

“Our mission is to simplify healthcare and make it more accessible,” said Cyrus Massoumi, ZocDoc cofounder and CEO.

The company claims to have over 1 million open appointments on its service. ZocDoc hopes to add to that number and plans on using the additional funding to expand its network of doctors nationally. The service is even running a contest where patients in US cities can vote to become the next ZocDoc market.

The new round brings the company’s fund raising total to about $19 million. With healthcare legislation giving 30 million new people access to healthcare, the company and its investors believe there is a significant opportunity in making it easier to schedule a doctor’s appointment.