Are online researches scientific?

This article is related to the use of internet in the scientific research process. The number of online researches have rapidly increased depending on technological developments and widely used internet. Online researches have some advantage, such as spending time, financial situation. Selection bias, volunteer effect, and generalization of results are important disadvantages of online researches. The most problem is the selection of sample. Because internet sample is not representative of the general population, it has not external validity. This situation is stated as ‘sampling error’. The basic principles for ethical problems are not determined. In this article, the advantages and disadvantages of online researches are reviewed. Because the sampling error is an important problem and not resolved yet, it is to say difficult that online researches are appropriate to scientific methods. (Anatolian Journal of Psychiatry 2020; 21(6):656-661) [Anadolu Psikiyatri Derg 2020; 21(6.000): 656-661]