Initially, it was a phone interview with the hiring manager. However, it took them couple of months to get back to me. I was invited to Merck's huge site at Kenilworth, NJ. The on-site interview was a day long interview and several of the interviews had 2 people interviewing at the same time. The interview also included an hour-long seminar. They also scheduled a lab tour in the agenda. Each person usually had a set of questions they would ask from. The questions were mixed between technical scenarios and behavioral type.