OBJECTIVE Assessing VNTR (variable-number tandem repeat) variability of Mycobacterium leprae from Colombian patients with and without prior treatment to identify potential sources of infection and to understand the patterns of disease transmission. METHODS This was a descriptive cross-sectional study where a convenience sample of biopsies was taken from 161 multibacillary leprosy patients; diagnosis and monitoring of the disease had been requested for these patients. DNA was extracted from M. leprae and standardised using the PCR technique for M. leprae VNTR, ge-notypes were established and different clusters grouped by unweighted pair group method with arithmetic mean (UPGMA). RESULTS 22 different VNTR genotypes were found from 161 samples, of which 100 samples (62.1%) had a single u-VNTR genotype and the remaining genotypes were VNTR 17 (5.6%), VNTR 20 (4.3%), VNTR 18 (4.3%), VNTR 14 (4.3%) and VNTR 13 (3.7%), namely those forming groups or clusters. CONCLUSIONS This study showed that clones can be detected with varying degrees of virulence / aggressiveness by cluster analysis, implying the need for more monitoring programme activities which will result in a real decline in microorganism transmission.