Osteoarthritis (OA) causes substantial pain and disability, especially among middle aged and elderly. The prevalence of knee OA is 10%. Risk factors of OA include female gender and elevated body mass index (BMI). OA is frequently associated with reports of physical disability. It reduces physical activity and increases the risk of cardiovascular diseases, like arterial hypertension (AH). AH affects 30% of world population and 15 to 20% of Brazilian population. Thus, many patients who are referred to physical therapy for OA of the knee are also hypertensive. There are studies that show the importance of aerobic and or strengthening exercises in control or as adjuvant to pharmacological treatment of AH. They can reduce blood pressure (BP). However, despite these exercises are applied in physical therapy for OA, their effects on AH are unknown. Therefore, we ask what are the effects of physical therapy on BP of hypertensive and normotensive subjects, during and after physical therapy sessions. The aim of this study, included in the research line Nursing and Health Caring Process, was to compare the BP values obtained, during and after a session of physical therapy. The subjects were divided into two paired by age groups: control group, composed of normotensive subjects without osteoarthritis of the knee, and experimental, composed of hypertensives with osteoarthritis of the knee treated at a universitary hospital of São Paulo state. They were selected using the Lequesne's algofunctional questionnaire and evaluated by a sociodemographic and clinical instrument and by physical therapy evaluation. BP was measured before, during and after physical therapy. The interval between consecutive measurements, was five minutes before the session and 20 minutes after the beginning of the session. Data were analyzed using the Chi-square and the Fischer exact test, Mann-Whitney test, Kruskal-Wallis and ANOVA for repeated measures followed by Tukey multiple comparison test, to compare the groups into each time and the contrast profile test to examine the evolution of the measures in each group (p< 0,05). More than 90% of subjects in both groups were female. Age (mean) was 57.22 years in control group and 60.58 in experimental group. In ix x control group, 52.17% of the subjects were not obese (BMI < 25). In the experimental group, BMI was shown to be in the range of obesity in 69.23% of the subjects. BP, both systolic and diastolic, increased throughout the period of collection in both groups. In disagreement with previous studies about effects of physical therapy on blood pressure, our results showed that therapeutic exercises should be applied with caution, because although they are not contra-indicated for normotensive or hypertensive, may cause elevation in BP levels, especially when the isometric exercise is part of the protocol of physical therapy .