From 2001 to 2010, the consumption of antibiotics in Denmark increased by 32%. The objective of this study was to investigate the potential demographic factors associated with this increase. Defined daily doses (DDD) per 1000 inhabitant-days for the leading antibiotic groups and substances in primary health care in 2001 and 2010 were adjusted for population size and compared between and within age groups and genders. An increased antibiotic consumption was observed for all age groups between 2001 and 2010. Particular age-specific increases in the consumption of tetracyclines, extended-spectrum penicillins, and amoxicillin/clavulanic acid were observed. The generally increased consumption of antibacterial agents in the Danish population during the past decade was driven by people older than 65 y and, to a lesser extent, those aged 20-39 y. Evidence suggests that this increase may reflect general practitioners prescribing more antibiotics per visit and in larger doses.