Objetive: To assess the impacto of a mindfulness program on physiological stress. emotional distress, perceived stress, and work stress in a group of workers. Material and methods: 28 universiy workers (employees and teachers) participated, who had registered high levels of work stress in a previous institutional evaluation. The program consisted of six training sessions in mindfulness once a week and with two hours per sessions (12 hours in total) with the techniques of mindfulness in breathing, in the body (body scan), thinking, emotions and break. Biofeedback measurements were used to evaluate five physiological stress indicators and three tests to measures. Results: blood volumen in the skin (d = 0.8), blood pulse (d = 0.8) and frequency of abdo-minal breathing (d = 0.9), emotional distess (d = 0.9), perceived stress (d = 0.7) and work stress (d = 0.6). Conclusión: mindfulness had a significant impact on stress reduction in university workers.