The purposes of this study were to describe breast self-examination (BSE) behavior; determine BSE and breast cancer knowledge as well as health beliefs; and examine the influence of BSE knowledge and health beliefs on BSE practice among women in three age groups: 35 to 45, 45 to 54, and 55 and older. The Health Belief Model was used to guide our study. The purposive sample consisted of 398 women aged 35 years and over in Korhong sub-district municipality, Songkhla province. Data were collected using questionnaires and analyzed using descriptive statistics and logistic regression analysis.

Results revealed that only 15-20% of women in the three age groups had performed monthly BSE and about half had never performed a BSE. The reason for never having performed a BSE was the lack of BSE knowledge and skills. The mean scores of perceived susceptibility and severity of breast cancer and perceived barriers to BSE of women in the three age groups were at a moderate level except for the perceived severity of women aged 55 years and over, which was at a high level. Women in all age groups perceived the benefits of BSE at a high level. Predictive factors of BSE among women in three age groups were different. In the youngest age group, knowledge of BSE was the only significant variable. For women aged 45 to 54 years, knowledge and perceived barriers were both significantly related to BSE. For the oldest age group, perceived barriers was the only significant predictor of BSE.