Serological tests can be helpful in classifying leprosy patients as having either the paucibacillary or the multibacillary form. The aim of this study was to evaluate the concordance between two serological assays, i.e. ML Flow and ELISA, in a population of leprosy patients in Brazil. The investigation involved 60 patients with newly diagnosed leprosy. Together with the application of the serological assays, selected demographic, clinical and epidemiological data relating to the study population were recorded. ML Flow detected anti-PGL1 antibodies in 70% of the leprosy patients, while ELISA was positive in 53.3%. The degree of concordance between the tests was substantial (83.3%). A positive correlation was demonstrated between the results obtained in the semi-quantitative ML Flow test and ELISA absorbance values. We concluded that both serological assays were found to be efficient in detecting anti-PGL1 antibodies. The ML Flow test may be a cheaper and easier to perform alternative to ELISA in leprosy patients.