Smartphone has become an essential part of human lives. People tend to treat it as another part of their body. Besides communication purposes, it is used for searching information, monetary transactions, shopping, social networking, entertainment, etc. This study aims at analysing the factors influencing smartphone usage and behavioural changes among college students under four constructs: utilisation, benefits, nomophobic behaviour and perceived risks (UBNR). An instrument was created with factors concerning the research and administered in a top-ranked private university of Bangalore, India. The research was carried out with a total of 122 responses. The results show that there is no significant difference in the attitude of males and females in most of the factors except social anxiety. Females experience more social anxiety and use smartphone more for maintaining their social relationships. There is no significant difference between the age group of students in all the four constructs. Utilisation is positively related with psychological, social, functional and financial benefits and shows that the greater the usage of smartphone, the greater are the benefits. On the other hand, the study reveals that increased usage of smartphone leads to addiction, causes nomophobia and poses threat of perceived risks. A mediation strategy like educating the students for proper use of technology is necessary to overcome the risk of addiction and developing nomophobia.