Osteoporosis is a skeletal chronic multifactorial disease characterised by abnormal low bone mass and microarchitectural deterioration of bone tissue. This disorder, present in both sexes, related to environmental and genetic factors, is becoming a major public health problem in developed countries. It has a polygenic pattern of inheritance that complicates identification of disease genes [cytokines, calciotropic hormones, sex hormones pathway synthesis and their receptors, bone matrix proteins synthesis genes involved on estrogenic metabolism (CYP19) and LDL receptor-related protein 5 (LRP5) gene]. It is possible to identify associations between candidate genes polymorphisms and disease phenotype in population-based and case-control studies. This could give us promising data for earlier identification of osteoporosis susceptibility and fracture risk. Preventive therapy could be targeted to patients at risk of osteoporosis before fractures occur. Genetic polymorphisms are also starting to be used to predict drug response. A new era of pharmacogenetics represents an interesting prospective to identify the potential individuals to receive customised treatments.