In this study, we have discussed the security of mobile phone services against information security threats during development process. The use of internet has increased on the mobile phones which makes the mobile phone and its services open for threats. These services are being attacked by different malicious software, or attackers. In our study, we have discussed how developers can secure mobile phone services against potential security threats and also we studied the vulnerabilities developers left during the development process. To achieve the goal of improving security in development process, we have discussed four major factors, development methodologies, IS awareness in developing process, vulnerability methodology and IS awareness training for developers. The awareness and training program helps to make changes in developers’ attitude, and also enforce them to consider and involve IS during development process. Further, the vulnerability methodology helps them to find flaws in services and secure it from attacks. Developer’s training and awareness program ends up with development of secure mobile phone services. Qualitative research approach with case study is being used as strategy. While data is collected with in-depth interviews. Before reading this thesis, a person should have background knowledge in the field of telecommunication because some part of this thesis contains some technical terms related to this field.