Objective:To assess the quality of mortality information by analyzing the frequency of garbage codes (GC) registered as underlying cause-of-death in Belo Horizonte, Minas Gerais, Brazil. Methods: Data of deaths of residents from 2011 to 2013 were selected. GC causes were classified as proposed by the Global Burden of Disease Study (GBD) 2015. They were grouped into GCs from ICD-10 Chapter XVIII and GCs excluding codes of Chapter XVIII. Proportions of GC were calculated by sex, age, and place of occurrence. Results: In Belo Horizonte, 30.5% of the total of 44,123 deaths were GC. Higher proportion of these codes was observed in children (1 to 4 years) and in people aged over 60 years. The following leading GCs observed were: other ill-defined and unspecified causes of death (code R99), unspecified pneumonia ( J18.9), unspecified stroke (hemorrhagic or ischemic) (I64), and unspecified septicemia (A41.9). The proportions of GC were 28.7% and 36.9% in deaths that occurred in hospitals and at home, respectively. An important difference occurred in the GC group from Chapter XVIII of ICD-10: 1.7% occurred in hospitals and 16.9% at home. Conclusion: The high proportions of GC in mortality statistics in Belo Horizonte demonstrated its importance for assessing the quality of information on causes of death.