The aim of this study was to assess upper limb morbidity following treatment for operable breast cancer. Patients were randomized to either mastectomy and axillary clearance (40 women: 12 with axillary nodal metastasis and 28 without axillary metastasis) or mastectomy and axillary sampling (54 women). Adjuvant radiotherapy was delivered to those in whom the sample revealed axillary nodal metastasis (28 women) but not to those with no axillary nodal metastasis (26 women). A subjective assessment of the state of the arm was made using a standard questionnaire. Objective assessment included upper and forearm circumference, shoulder joint mobility and assessment of power in the pectoralis muscle. The mean age was 56·8 years (range 33–77 years) and the mean elapsed time from treatment was 5·72 years (range 4·0–7·5 years). Subjective limb oedema was greatest in those who had axillary lymph node metastasis but there was no objective difference. Subjective joint mobility was reduced in the women who received radiotherapy and this was confirmed by objective assessment (P<0·05). The objective reduction in arm mobility was related to the treatment rather than the axillary lymph node status. There was no difference in power. In this study women receiving adjuvant radiotherapy had significantly reduced shoulder mobility. This may have implications for current conservation studies using adjuvant radiotherapy.