We estimate the prevalence and evaluate the clinical characteristics of leprosy related arthritis. One thousand, two hundred fifty-seven leprosy patients were attended at "Alfredo da Matta" outpatient clinic in the state of Amazonas, Brazil from July to October 2004. Among them, 115 patients were identified with articular pain and were referred for evaluation with rheumatologist. Blood samples were collected and radiological evaluation of the involved joints was performed. All patients with arthritis who continued to be followed up were reevaluated. One hundred fifteen leprosy patients (9.1%) were identified with articular involvement. The articular complaints were attributed to a defined rheumatic disease in 36 cases and excluded from further analysis. Twenty-four patients had arthralgia, and 55 (37 males and 18 females) had leprosy-related arthritis. The prevalence of arthritis was similar in both genders, and all patients with leprosy-related arthritis had lepromatous or borderline type. Most of patients had polyarticular and symmetrical arthritis and had completed the multidrug therapy and was under reaction treatment. The mean duration of articular symptoms at the time of study was 1.06 years (ranging from 5 days to 14 years). Ninety-one percent of patients with leprosy-related arthritis presented erythema nodosum leprosum or reversal reactions. Only five patients with arthritis had never presented reactions. Fifty percent of patients became asymptomatic during the mean 24 months of follow-up. Leprosy-related arthritis has a lower prevalence than previously reported. Most cases of leprosy-related arthritis were associated with reactional episodes, and in a large number of cases, the arthritis had a chronic course not responsive to the conventional therapy for reactions.