Despite dramatic increases in prescription drug abuse, very little research has examined the role that provider characteristics and physician networks play in inappropriate prescribing. Recent work that has begun to address physician prescribing deviance is dominated by the perspective that the prescription drug epidemic is primarily driven by a few prolific deviant physicians in corrupt pill mills who are frequented by doctor-shopping patients. We distinguish between prescribing deviance by omission and commission and examine factors associated with each. Physicians engaged in deviance by omission, which has received limited attention from researchers and policy makers, have a substantial effect on the total volume of benzodiazepines prescribed. Using a longitudinal patient-sharing network comprised of 660,428 physicians linked by 12.5 million patients, we find remarkable differences in the characteristics and networks of physicians engaged in deviance by omission and commission. Taking these differences into account will improve efforts to curb prescription drug misuse by allowing for more effective targeting of educational and policy efforts aimed at reducing inappropriate prescribing.