Sports motivation is a significant object of research in sports science; therefore, it is important to apply reliable research instruments to investigate it. The sport motivation scale is one of such instruments (Pelletier et al., 1995). In the context of Lithuania, the sport motivation scale has been applied in doctoral research to measure sports motivation of adolescents attending orienteering sport and sports tourism. Later this version of the scale was applied in Lithuania in several research works. It should be noted that all research works carried out in the populations of children and adolescents doing sports in Lithuania were limited by young athletes representing one or two sports, and the samples were quite small. The demand for an instrument to measure sports motivation as well as the cause of insufficient psychometric investigation of the sport motivation scale determined the aim of this research: to psychometrically assess the Lithuanian version of the sport motivation scale. Motivation of young athletes has been measured by the sport motivation scale (Pelletier et al., 1995). The process of translation of the sport motivation scale into Lithuanian and its correction proceeded in several stages. The research involved 688 young athletes (463 boys and 225 girls) from various sports schools and other nonformal institutions of education in Lithuania. The age of the surveyed varied around 14–18 years, the average age was 15.61 ± 1.97 years. The average duration of attending sports clubs was 4.74 ± 2.88 years. Reliability and inner coherence of the subscales have been found grounding on the following: 1) Cronbach α coefficient; 2) correlations of the statement with the subscale by the ITC (Item-total Correlation) coefficient and 3) Cronbach α coefficient, efficient having eliminated the statement (α e.t.). Linear statistical links between the variables have been found out by applying Spearman correlation coefficient. Values of Cronbach α coefficient varied from 0.65 to 0.80, average was 0.72. The minimal value of the coefficient of the correlation of separate statements with subscales varied from 0.36 to 0.57, and maximum was from 0.52 to 0.66. After Cronbach α eliminated the statement, the test showed that, having eliminated any statement from the subscale, values of Cronbach α coefficient would not increase. Values of Cronbach α coefficient are very close to the original version of the sport motivation scale. In research by Pelletier et al. (1995), Cronbach α coefficient varied from 0.63 to 0.80, and the average was 0.75. The main advantage of this research lies in design and psychometric assessment of the Lithuanian scale to measure sports motivation. The research is highly relevant in the context of sports science in Lithuania because it is the first questionnaire on sports motivation grounded on the theory of resolution. Psychometric parameters of the Lithuanian scale aimed to measure sports motivation are quite good; therefore, the scale is suitable to measure and assess manifestation of young (14–18 years) athletes’ motivation in the context of self-determination theory. Keywords: sport motivation scale, sports motivation, self-determination theory, psychometrics. DOI: http://dx.doi.org/10.15823/sm.2017.13