To determine the average time in months between the beginning of symptoms and the diagnostic confirmation of leprosy by the health system and to investigate factors associated with diagnostic delay.A total of 249 patients older than 15 years diagnosed with leprosy between 2011 and 2015, in 20 endemic municipalities of north-eastern Colombia, provided informed consent and were interviewed face-to-face. Clinical histories from health centres or hospitals where study participants were treated for leprosy were also reviewed.The mean delay in diagnosis of leprosy was 33.5 months. About 14.9% of patients showed a visible deformity or damage (disability grade 2, DG2) at the time of diagnosis. In multivariable regression analysis, five or more consultancies required to confirm the diagnosis and not seeking care immediately after noticing first symptoms were associated with longer diagnostic delay.Our study found a significant delay in diagnosis of leprosy in north-eastern Colombia, which might explain the continuously high rate of DG2 among new cases being notified in the country. Both patient- and health system-related factors were associated with longer diagnostic delay. Interventions to increase awareness of disease among the general population and timely referral to a specialised health professional are urgently needed in our study setting.