OBJECTIVES: Stress urinary incontinence (SUI) is a common condition in women, caused by anatomical problems related to factors such as age, parity, white race, hormonal state, higher educational attainment, pregnancy related factor and higher body mass index. Several studies indicate obesity as an important SUI related factor. This study was conducted to investigate the impact of obesity in the quality of life of women with urinary incontinence. METHODS: Women with the symptom of SUI were recruited prospectively over a 3-months period from a tertiary referral urogynaecology center in a teaching hospital. A group of 86 women complaining of SUI and confirmed as having SUI on urodynamic assessment agreed to participate. The King's Health Questionnaire (KHQ) was applied before any treatment to assess the impact of SUI in the quality of life. We then divided the patients in two groups, obese and non obese women, according to their BMI (>30 BMI and <30 BMI) and compared them using Student t test. RESULTS: There were 25 patients in the obese group and 61 in the non obese group. There were no statistical differences between the groups concerning, age, number of pregnancies, height and daytime frequency. The obese patient group was heavier (p<0.0000), with greater BMI (p<0.0000) with an also statistically greater nighttime frequency (p= 0.0147). The obese group had more time of SUI symptoms complain (p= 0.0268). Of the evaluated domains of the KHQ (general health perception, incontinence impact, role limitations, physical limitations, social limitations, personal relationships, emotions, sleep/energy, severity measures) only the severity measures were statistically different among these two groups (p= 0.0093). CONCLUSION: Obesity seems to aggravate the perception of the severity of the urinary incontinence problem in women.