This paper reports the quality of life (QoL) of a large cohort of Australian women three and twelve months after surgery for early stage breast cancer (ESBC), and shows that the impact of disease and treatment on QoL differed by age, education and marital status. Eighty-three percent of eligible patients were recruited; 86% had breast conserving surgery and 14% mastectomy. Response rates were 93% (n = 305) at three months and 88% (n = 291) at one year. Quality of life was measured with the EORTC core questionnaire (QLQ-C30) and an ESBC-specific questionnaire. Multilevel analysis was used to estimate the effects and interactions of time, treatment and patient characteristics. Most symptoms declined between three months and one year, but arm and menopausal symptoms persisted. Emotional, social and role functioning improved over time, and fear of disease recurrence diminished. Younger women faired worse than older women on a broad range of QoL dimensions. Single women and those with less education faired worse on a number of dimensions. The negative impact of mastectomy on body image was greatest among married women, particularly young married women. These sociodemographic distinctions are relevant when discussing treatment options with women facing a diagnosis of ESBC.