The objective of the MAPPING study was to estimate the prevalence of musculoskeletal conditions in an Italian population sample. Questionnaires were sent to a random sample of 3664 individuals aged 18 years and over, stratified for age and gender, selected from the practice lists of 16 general practices. Trained rheumatologists carried out structured visits in which subjects were asked about musculoskeletal symptoms and socio-demographic characteristics, and underwent a standardized physical examination. Cases were defined by previously validated criteria. A total of 2155 subjects participated in the study (response rate 58.8%). The overall prevalence of musculoskeletal conditions in the general adult population was 26.7% (95% CI 25.4-28.5), being significantly higher among women than men (p < 0.0001). Disease prevalence increased significantly with age (p < 0.0001). The most common disease group was symptomatic peripheral osteoarthritis (SPOA), with a prevalence of 8.95% (95% CI 6.81-10.7), followed by soft tissue disorders--STD (8.81%; 95% CI 7.16-10.29), low back pain--LBP (5.91%; 95% CI 4.89-6.89), and inflammatory rheumatic disease--IRD (3.06%; 95% CI 2.38-3.93). The estimated rates of disease prevalence were as follows: rheumatoid arthritis: 0.46% (95% CI 0.33-0.59); psoriatic arthritis: 0.42% (95% CI 0.31-0.61); ankylosing spondylitis: 0.37% (95% CI 0.23-0.49); polymyalgia rheumatica: 0.37% (95% CI 0.29-0.44); undifferentiated connective tissue disease: 0.14% (95% CI 0.09-0.21); crystal arthropathies, including gout 0.46% (95% CI 0.34-0.57) and chondrocalcinosis: 0.42% (95% CI 0.33-0.58); symptomatic knee osteoarthritis (OA): 5.39% (95% CI 3.41-7.99); hip-OA: 1.61% (95% CI 1.39-1.87); hand-OA: 1.95 (95% CI 1.22-2.48); fibromyalgia: 2.22% (95% CI 1.36-3.19); shoulder tendinitis/adhesive capsulitis: 3.06% (95% CI 2.11-4.09); carpal tunnel syndrome: 1.90% (95% CI 1.06-2.29), localized regional pain syndromes of the neck: 0.88% (95% CI 0.561.29), and lateral epicondylitis 0.74% (95% CI 0.47-1.33). The MAPPING study indicates that musculoskeletal conditions are common in the general adult population of Italy. These data are useful in planning the provision of healthcare.