The purpose of this pilot study was to gather information on the immediate and short-term effects of relaxation training according to Yoga In Daily Life(®) (YIDL) system on the psychological distress of breast cancer patients. 32 patients at the Institute for Oncology of Ljubljana were randomized to the experimental (N=16) and to the control group (N=16). Both groups received the same standard physiotherapy for 1 week, while the experimental group additionally received a group relaxation training sessions according to YIDL(®) system. At discharge the experimental group was issued with audiocassette recordings containing the similar instructions for relaxation training to be practiced individually at home (for further 3 weeks). An experimental repeated measures design was used to investigate the differences over 1 month period in stress levels, changes in mental health and psychological parameters. Measures were obtained at three time points during the study period: baseline, at 1 week, and at 4 weeks, by blinded investigators using standardized questionnaires General Health Questionnaire-12 (GHQ-12), Rotterdam Symptom Checklist (RSCL) psychological subscale, Perceived Stress Scale (PSS). Patients who received relaxation training reported feeling significantly less distressed during hospitalization and after discharge-period than did the controls that did not receive relaxation training. The results indicate that relaxation training according to Yoga in Daily Life(®) system could be useful clinical physiotherapy intervention for breast cancer patients experiencing psychological distress. Although this kind of relaxation training can be applied to clinical oncology in Slovenia, more studies need to be done.