OBJECTIVES: To assess the prevalence and incidence of osteoporosis, determine recent and predict future time trends in the Dutch population in the period 1993-2015. METHODS: Data were obtained from the PHARMO database, which includes linked drug-dispensing records and hospital records of more than 865,000 subjects in defined areas in the Netherlands. Patients (>45 years) who were hospitalised for osteoporosis (ICD9-CM: 733) or osteoporotic fractures (ICD-9-CM: 820, 812.0, 813.4, 805.2 and 805.4) and treated with glucocorticoids or anti-osteoporosis drugs (bisphosphonates, vitamin D, calcium, ralixofen, HRT) between 1993 and 2002 were included. Prevalence of osteoporosis was calculated as the total number of patients having osteoporosis on a single fixed day in a year (first Wednesday of October). Incidence of osteoporosis was computed as the number of new cases that met the inclusion criteria in a certain year divided by total person-time contributed by the population at risk. RESULTS: A total of 32,219 patients were included in this cohort. Prevalence of osteoporosis increased from 36 in 1994 to 56 in 2002 per 1,000 inhabitants. Incidence declined in the same period from 8.7 to 7.0 (per 1,000 inhabitants.). Extrapolations based on demographic changes in the future indicate that prevalence of osteoporosis will increase up to more than 65 (per 1,000 inhabitants) in 2015. CONCLUSIONS: Prevalence of osteoporosis has been continuously increasing over the past decade. Our data show that the pace of this increase slowly declines probably due to increased awareness and screening that leads to a decrease in the size of the ‘pool’ of undetected osteoporotic patients. Ageing of the population is becoming the predominant contributor to a further increase of the osteoporosis prevalence in the future causing great social and economic burden to the society. Prevention of osteoporosis and its consequences is critical to reducing this burden.