Currently, banks play an important role in growth and development of an organizations in all countries. Malaysian banks offer Internet banking service where Internet banking service is gaining popularity and acknowledge all over Malaysia, this new services among Muslims consumers' is still low. Investigation on Muslims consumers that uses Internet banking are still rare. Hence, this paper examine the results of the usage and the level of customer s satisfaction of online users in Islamic banks through descriptive and explanatory approach by conducting a survey from 201 young adult participants. The objectives are to investigate the level of satisfaction of the online banking services in Islamic banks and to investigate whether convenience is most important factor to satisfy internet banking user of young adults. The outcome was shown that speed and accessibility are the most important factor that influence customers satisfaction in online banking and that they frequently make their online transaction weekly. These results were corresponded with past researches. Lastly, most of respondents are satisfied with their bank s current online banking services. Overall, the studies concluded that convenience which is high speed and accessibility are the most important factor to satisfy the online banking users. Limitations of the study are highlighted and further research directions are suggested.