Drawing on the 1998, 2003, and 2009 "Health Barometer" surveys of general practitioners, INPES and IRDES analyze here—based on nationally representative samples—group practice among private general practitioners, its characteristics, and its evolution. Group practice is now the norm. The proportion of private general practitioners reporting that they work in group practices rose from 43% in 1998 to 54% in 2009. This increase is particularly pronounced among doctors under 40, nearly eight out of ten of whom work in group practices. Three-quarters of general practitioners working in group practices do so in practices composed exclusively of general practitioners and/or specialists. Most of these practices consist of two or three practitioners. Group practice also appears to alter the weekly work schedule of general practitioners without changing their overall weekly workload: general practitioners working in groups report working fewer than five days per week more often but performing more procedures per day than those practicing alone. Group practice is also associated with a practice model that allows more time for training and supervising students and relies more frequently on computer technology.[author’s summary]