2 interviews. First one on campus consisted of 2 45 minute interviews with a Project Leader and Principal. Second interivew consisted of 3 45 minute interviews in the office I applied to, 2 of which were with Partners and one with a Principal. Each interview consisted of a few minutes of the typical interview (tell me about yourself, why consulting, why BCG, tell me about a time when... etc.) and a case interview (suppose X company is thinking about expanding into Y market - should they do it?) that was very difficult.