Predicting customers’ intention to purchase products online is an important issue. This thesis aims to understand how online shopping decision is determined by individual’s intention to buy via Internet and his/her attitude toward e-purchase. This study by integrating the Theory of Reasoned Action (TRA) with the Technology Acceptance Model (TAM), attempts to understand how website usefulness and ease of use, as well as customers’ attitude toward online shopping, influence purchase intention influence the online purchase. Those two models adopted in an online environment were used to analyze the outcome of the survey among Polish e-shoppers. By adopting the idea of regular and heavy Internet users, this study tries to differentiate the online shopping behavior in those two groups. The findings of the thesis have been found to be partially consistent with both models. However the difference between heavy and regular Internet users in frequency of buying online has not been confirmed.