This study was designed to assess the percentage share of musculus obliquus externus abdominis, musculus obliquus internus abdominis and musculus transversus abdominis activity among women suffering from stress urinary incontinence using ultrasound imaging. The study is a retrospective analysis of prospective collected data of 84 women aged 23-62 years. In the study group are women suffering from grade 1 or 2 stress urinary incontinence according to the Stamey classification; the control group consists of women with no micturition disorders. The abdominal muscles' activity was measured by using ultrasound imaging with assessment of muscle thickness. The analysis of musculus obliquus externus abdominis in anterolateral abdominal wall activity shows a statistically significant difference between study and control groups concerning isometric tension of abdominal muscles (p = 0.012) and lower abdomen tension (p = 0.004). Women with stress urinary incontinence present higher activity of the musculus obliquus externus abdominis than women in the control group. In the case of the musculus obliquus internus abdominis, statistically significant differences were found during tension of the lower part of the abdomen (p = 0.024). Comparison of activity of the musculus transversus abdominis between study and control groups shows a statistically significant difference during isometric tension of abdominal muscles (p = 0.018). The pattern of activity of the assessed muscles differs between the study group and the control group. In the study group, the activity pattern concerns the higher activity of the musculus obliquus externus abdominis and the lower activity of the musculus obliquus internus abdominis and musculus transversus abdominis.