Adolescence is the word derived from Latin word Adolescere meaning to grow up to maturity. It is a transitional stage of physical and psychological development that usually occurs during the period starting from puberty to legal adulthood i.e. age of maturity. Adolescence is associated with 10 yrs. to 19 yrs. of age (World Health Organization, 2017); In comparison to girls, boys begin their growth spurt about two years later, usually between the ages of 10 years to 16 years and reach their adult height between the ages of 13 years to 17 years. During these years, males grow muscle much faster than female, an adolescent‟s heart and lungs increase in both size and capacity. The growth spert is very high , shoulders will broaden and his body muscles will develop. Hormones will produce more oil on his skin and may result in acne breakouts. Testicles will begin to grow, penis begins by growing in length, followed by width. To be aware about theses developmental changes, intervention is must , specially to early adolescent boys as girls are getting it‟s knowledge from family and community whereas boys are deprived from this awareness.Awareness is knowledge about the state of some environment. It is a term used to denote knowledge created through the interaction of an agent and its environment , in simple terms knowing, what is going is awareness . Now a days more advanced mobile phone technologies are enabling the potential for education and early adolescent boys are more engaged in browsing mobile devices. Researchers found that the usages of mobile apps. strongly correlates with user context and depends on user‟s location and time of the day. Mobile phone apps. are playing an ever-increasing role within healthcare and when designed and integrated correctly can yield many benefits. So after developing need based mobile app. on selected developmental changes during early adolescent stage , intervention was provided through developed need based mobile app. for a month to the respondents of experimental group , it can be concluded that the provided intervention through developed mobile phoneapp.,regarding selected developmental changes has significantly positive impact on awareness levels of early adolescent boys of experimental group,where as very slight and negligible change were found in control group respondents , which indicates the emergency of intervention to early adolescent boys.