Although Canadian Breast Screening Guidelines have been in place since 1988, participation rates have been suboptimal. The study objective was to describe changes in breast screening knowledge, attitudes, and practices among women aged 50 to 69 years since initiation of a regional mass screening program in Ottawa-Carleton in 1991. A random-digit-dialing telephone survey was conducted with 384 women aged 50 to 69 years residing in Ottawa-Carleton and compared to a 1991 survey. Between 1991 and 1994 there were significant increases in the percentage ever having had a mammogram (from 60% to 83%) and monthly breast self-examination (from 46% to 54%). Professional breast examination rates were unchanged as were overall attitudes and concerns about screening. There were significant improvements in knowledge and encouragement to have a mammogram. As the focus on primary health care within our health care system grows, and as service delivery changes, we must continue to search for, and continually evaluate, innovative strategies to align practices with Canadian breast screening recommendations.