Bone is a living, dynamic tissue that undergoes constant remodeling through life.This is necessary to allow the skeleton to increase in size during growth, respond to the physical stresses placed on it and repair structural damage due to structural fatigue or fracture. This process requires range of proteins and minerals,which are absorbed from the blood stream. Osteoporosis often known as the silent thief because bone loss occurs without symptoms; one in four women over the age of 50 has osteoporosis. One in eight men over 50 year also has the disease. However,the disease can strike at any age. More women die each year as a result of osteoporotic fractures than from breast and ovarian cancer. This study is the Quasi experimental -one group pre test post test design to assess the effectiveness of STP on osteoporosis among middle aged women.In this study non-probability sampling technique with convenient sampling was used. Sample size consists of 50 middle aged women. The overall knowledge score in pre test is 14.300 and post test score is 26.260. The paired t-test score (21.532) shows that the Structured Teaching Programme has effectiveness on increasing knowledge of middle aged women regarding osteoporosis and its prevention.It is revealed that there is significant association between the post test knowledge score with education (Chi-square=4.920) and occupation (Chi-square value=5.048). The association was calculated using Chi square test. Therefore the Research hypothesis H2 has been accepted.