During the past few years, electronic marketing has gained significant portion of market share in the world. People become familiar with various products and services through the magic of internet and they could make their purchase with an ease of a click of a button. This paper presents an investigation on important factors influencing e-marketing in banking industry in city of Tehran, Iran. The proposed study designs a questionnaire in Likert scale consists of 19 questions, distributes it among 250 Iranian experts and analyzes it based on principal component analysis. During the survey, the numbers of questions are reduced to 16. Cronbach alpha is calculated as 0.90 and Kaiser-MeyerOlkin Measure of Sampling Adequacy and Approx. Chi-Square are 0.939 and 2938, respectively. Based on the results of our survey, we have derived two factors including environmental factors as well as information technology.