The purpose of this pilot study was to gather information on the immediate and short-term effects of relaxation training according to the Yoga In Daily Life® (YIDL®) system on anxiety of breast cancer patients. The YIDL® system is a holistic system being practised and taught worldwide and has been proven to be highly effective in the prevention and treatment of various diseases. The system aims to establish physical, mental, spiritual, and social health. Thirty-two patients at the Institute for Oncology Ljubljana were randomized to the experimental (n=16) and to the control groups (n=16). Both groups received the same standard physiotherapy for 1 week, while the experimental group additionally received 1-hour group relaxation training session according to the YIDL® system per day. At discharge, the experimental group was issued with audiocassette recordings containing similar instructions for relaxation training to be practiced for 3 weeks individually at home. Anxiety measures were obtained by blinded assessors using standardized questionnaires. The results indicate that relaxation training according to the YIDL® system could be a useful clinical physiotherapy intervention for breast cancer patients experiencing anxiety.