This study has been conducted to evaluate the effect of the prolonged mechanical passive stretch (PMS) in elongating the gastrocnemius – soleus muscles and the reflection of that on some quantitative gait parameters and the range of motion (ROM) of both knee extension and ankle dorsiflexion. Twenty male patients were participated in this study, who were selected from Cairo University Hospitals with a second degree posterior leg burn and a total body surface area of 15-20%. They were divided randomly into two groups of equal number, group (A), 10 patients who were 20-30 years of age (X=25+3.4), that received the PMS plus the traditional physical therapy program (positioning and exercises) and group (B), 10 patients who were 20-30 years of age (X=24.4+3.75), that received only the same traditional physical therapy program and acted as a control group. Measurements were recorded before treatment and at the end of the first, second and third week of treatment (session for 30 minutes, twice/day, on 5 days / week bases for a total period of 3 weeks). A 16-meter walkway, tape measure and stop watch were used to measure the quantitative gait parameters, while a standard gomiometer was used to measure the knee extension and ankle dorsiflexion ROM. Results of this study revealed that the PMS was effective in elongating, the gastrocnemius – soleus muscles as reflected by the improved gait parameters as well as the ROM of both knee extension and ankle dorsiflexion.