Objective: To evaluate hand hygiene compliance of health care workers in a Colombian private hospital. Methods: A cross sectional study was conducted. Information was recorded about hand hygiene at the appropriate moment (hand hygiene opportunity) by means of direct observation. Compliance was defined as hand hygiene according to Clinica de los Andes ICU hand hygiene guidelines. Results were analyzed by a mixed-effects model. Results: One hundred eighty opportunities corresponding to 26 health care workers were observed. Overall compliance was 18.9%, and varied according to the worker (especially nurse assistants and physical therapists), and with timing related to patient contact. Multivariate analysis showed a protective OR for noncompliance following contact (OR= 0.23. CI 95% 0.15-0.33). Conclusions: Low compliance suggests the need for the development of specialized intervention models for health care professionals who are already aware of the benefits of hand washing.