This study aimed at identifying the hospitalization costs of pregnant women with Diabetes Mellitus (DM) at a University Hospital. It is an observational, quantitative study with descriptive data analysis. The direct and indirect costs available in the institution were identified in order to determine the hospitalization costs for patients diagnosed with DM during pregnancy and childbirth. By means of descriptive statistics, it was observed that 63.46% of the patients had caesarean delivery; the mean total cost was R$ 362.93 (U$ 218.10)/hospitalization during pregnancy, R$ 2,642.65 (U$ 1,588.13)/hospitalization for caesarean delivery, and R$ 2.319.77 (U$ 1,394.09)/hospitalization for vaginal delivery. It was concluded that the analysis of hospitalization costs for patients with DM is of utmost importance, since they are highcomplexity hospitalizations that require a large number of interventions, increasing thus the service costs.