Vitamin D deficiency may be one important contributing risk factor for an osteoporotic fracture among elderly. We analyzed serum 25-hydroxyvitamin D [S-25(OH)D] status in patients with an acute hip fracture in southeastern Finland (61 degrees N). Consecutive patients with a fresh hip fracture (n=223) in two Finnish hospitals during 12 months and 15 months were registered prospectively. S-25(OH)D concentrations (nmol/l) were measured by radioimmunoassay-method. Hypovitaminosis D was defined as S-25(OH)D < 37.5 nmol/l and severe hypovitaminosis D: < 20 nmol/l. The highest threshold of S-25(OH)D in our analysis was > 74 nmol/l. The seasonal variation in S-25(OH)D concentrations was followed. Hypovitaminosis D was found in 53% of the patients. In 9% hypovitaminosis D was severe. Half (50%) of the patients living in their own homes, 55% of those in residential homes, and 61% of institutionalized elderly had hypovitaminosis D. Patients who used both vitamin D and calcium supplement had S-25(OH)D levels between 37.5 nmol/l and 74 nmol/l and > 74 nmol/l more often than non-users (Wx=3.85, p=0.0001). Most (41/61) of the patients who sustained the fracture during the late summer months had S-25(OH)D concentration > or = 37.5 nmol/l, whereas, in winter months the situation was quite the opposite (24/67) (Wx=3.42, p=0.0006). Twenty-two percent (50/223) had S-25(OH)D concentration > 50 nmol/l and four patients > 78 nmol/l. Half of the patients with a hip fracture suffered from hypovitaminosis D. The situation was worst in institutional and residential care, although there are personnel for taking care of vitamin D supplementation. In the late summer, one-third and in late winter two-thirds of the patients suffered from hypovitaminosis D. The geographical location of Finland indicates extensive efforts to increase the use of vitamin D supplements among elderly.