Purpose Osteoporosis (Op) and metabolic syndrome (MetS) are two common disorders showing common pathogenic patterns. This cross-sectional study was performed to evaluate if MetS and its constitutive elements are associated to an increased risk of low bone mineral density (BMD) in free-living women examined by Dual-energy X-ray absorptiometry (DXA) for suspected Op. Methods 13,182 free-living Caucasian women referring to “COMEGEN” general practitioners cooperative operating in Naples, Italy, performed a contextual evaluation of BMD by DXA and all MetS constitutive elements (systolic and diastolic blood pressure, waist circumference, serum levels of triglycerides, high-density lipoprotein cholesterol, and fasting glucose) between June 1st 2008 and May 31st 2018. Subjects aged less than 40 years or with signs or symptoms suggestive of secondary Op were excluded from the study. Results MetS is associated to an increased risk of low BMD (Odds Ratio 1.19; 95% Confidence Interval 1.08–1.31). Among MetS constitutive elements, hypertension was associated to increased risk of low BMD, whereas high fasting glucose level/diabetes were associated to reduced risk of low BMD. Conclusions The significant association between Op and MetS in free-living women examined by DXA for suspected Op suggests the advisability of a contextual evaluation of both disorders in this setting.