Human spend one quarter of life in sleep. However, not everyone gets adequate sleep as there are factors that can disturb sleep that can lead toinsomnia. One of the behavioural factors that can influence sleep is the consumption of caffeinated drinks. The purpose of the present study was toidentify the lifestyle factor for insomnia such as consumption of caffeinated drink (tea and coffee). The participants were 500 working adults aged20-60 years in Georgetown, Penang who were relatively healthy. The participants were recruited through convenience sampling at various workingplaces. Athen’s Insomnia Scale (AIS) was administered to screen on insomnia symptoms. 135 respondents who had insomnia symptoms wereassessed on consumption of caffeinated drink in daytime and close to bedtime through descriptive questions. Interestingly, our finding showedinsomnia did not increase with age, younger adults experienced more insomnia also the caffeine consumption among these adults were higher.The results revealed that consumption of caffeine in daytime and close to bedtime among young age-group significantly predicted insomnia. Thisfinding may help to increase the awareness that sleep among young individuals can be disturbed by unhealthy lifestyle, thus it is imperative totake preventive measure against insomnia.