OBJECTIVE: To explore the association between fat intake, serum lipids and the risk of osteoporotic fractures in the elderly. DESIGN: A hospital-based case-control study. SETTING: The study was conducted at a tertiary centre and referral hospital for the province of Jaén (Spain). SUBJECTS: Cases (n=167) were patients aged 65 years or more with a low-energy fracture selected from the population attended at the hospital. Controls (patients without antecedents of any fracture) were 1:1 matched to cases by sex and age (n=167). METHODS: Diet was assessed by a semiquantitative food frequency questionnaire. Serum total cholesterol and high-density lipoprotein (HDL) cholesterol were also measured. RESULTS: Participants in the two upper quartiles of polyunsaturated fat (PUFA) intake showed an increased risk of fracture, with statistically significant differences with respect to the first quartile in the adjusted model (odds ratio (OR)=3.59; 95% confidence interval (CI)=1.06-12.1 and OR=5.88; 95% CI=1.38-25.02); P=0.01 for the trend test). A higher ratio of monounsaturated fat (MUFA) to PUFA was associated with a reduced risk of fracture (OR=0.20; 95% CI=0.07-0.60 for the fourth quartile; P=0.002 for the trend test). The intake of omega-6 fatty acids was associated with an elevated risk of fracture (OR=3.41; 95% CI=1.05-11.15 for the fourth quartile; P=0.01 for the trend test). HDL-cholesterol levels were inversely associated with the risk of fracture (test for trend P=0.03 across quartiles). CONCLUSIONS: PUFA intake was associated with an increased risk of osteoporotic fractures in the elderly, whereas a high ratio of MUFA:PUFA was associated with decreased risk.