Background This study aimed to identify the perinatal mortality coefficient, the epidemiological profile, causes and avoidable factors at a reference public maternity hospital in southern Brazil. Methods In this cross-sectional study, 334 medical records of postpartum women and newborns were evaluated between January 1st, 2011 and December 31st, 2015. The Expanded Wigglesworth Classification was used to assess the causes of perinatal mortality and the International Statistical Classification of Diseases and Related Health Problems (ICD-10/SEADE Foundation) was used for the preventable perinatal mortality analysis. Absolute numbers and percentages were used for data analysis. The perinatal mortality formula was used to calculate the perinatal mortality rate. Results The perinatal mortality rate was 13.2/1000 total births, with a predominance of white race/color; mothers were 21-30 years of age, had experienced their first pregnancy and had completed their high school education. Conclusion The main factors associated with perinatal death were antepartum fetal death in 182 (54.49%) cases, and avoidable death through appropriate prenatal care in 234 (70.05%) cases.