Women are a minority among STEM undergraduate programs in Chile. Less than 20% of the students enrolled in technology-related careers are women, according to the Chilean Higher Education Information Services. The absence of gender-related data on attrition rates among students of these programs in Chile is the main motivation of this work. We conducted a descriptive study of attrition in the Informatics undergraduate program at the UTFSM, a STEMfocused university in Chile. On average, 10% of the new students of the program are female. In the last five years, our program has had a mean attrition rate of 24% during the first year, while 30% of our female students drop out. Their score in the admission test explains to a greater extent both their academic performance in the undergraduate program and their decision to stay/leave, but not completely. Many of the female students with high performance in the mathematics admission test drop out of their studies in the first year. The reasons for their departure remain unclear.