Internet addiction and pathological gambling are nowadays becoming an increasing public health problem. It hasn't still been totally clarified whether, when dealing with no substance addiction, we are still talking about real addiction that includes the same pathophysiological processes at the biological level or we are dealing with impulse control disorder, the reason why the goal of this research has been to see whether the subjects who spend their time investing in the stock market met the criteria for addiction according to DSM-IV TR classification of psychiatric disorders. Research was conducted using a modified self-made IAT questionnaire that was available on the web portals Poslovni.hr and Moj Novac.hr. People who invest in the stock market and trade stocks online were invited to fill out this questionnaire. Questionnaire consisted of 13 questions: 3 about demographic indicator of respondents, 3 about time spent in investing in the stock market and frequency of monitoring developments in the stock market and 7 questions were prepared according to the DSM-IV criteria that define the existence of addiction. The questionnaire was fully completed by 111 respondents, the majority of which were men age 35-45 and highly educated. Most respondents invested for more than one year and were daily monitoring developments in the stock market for 1-6 hours. Regardless of the type of classification answers,most of the respondents have more than 3 positive criteria for addiction (when taking the mild classification it is 96,4% of respondents, and according to the strict classification it is 81,1% of the respondents). According to the results of our study, the majority of respondents who spend time online investing on the stock market and trading stocks met the criteria for the existence of addiction according to DSM-IV classification of psychiatric disorders.