Risky behavior can be defined as behavior with adverse consequences for the person who manifests it and in this study is presented in the form of alcohol consumption, smoking tobacco and marijuana. Some studies suggest that birth order is a significant determinant of risky behavior. Ordinal position that one gain by birth within the family represents his birth order. A review of available related studies showed that later born children are more rebellious compared to the first-born children (Paulhus et al., 1999; Healey and Ellis, 2007, according to Eckstein et al., 2010). Children who have older siblings are more likely to exhibit risky behaviors such as alcohol consumption, smoking tobacco and marijuana that can be considered as an act of rebellion (Argys et al., 2006; Laird and Shelton, 2006; Averett et al., 2011; Horner et al., 2012). The main aim of this study was to determine the level of risky behavior among young people in the form of tobacco, marijuana and alcohol consumption considering birth order measured by Adler's, dichotomous, serial and continuous method. The study was conducted on a sample of 266 participants (63 males and 203 females) between the ages of 18-28 years. In order to provide an answer to these problems, an on-line questionnaire, which collected data about participants birth order and their level of risky behavior, was applied. The analysis of the data showed no difference in the level of risky behavior due to the birth order that can be explained by methodological shortcomings of the research. Furthermore, no significant correlations between birth order measured by various methods and tobacco, marijuana and alcohol consumption were found.