The present study was performed to measure the precompetitive anxiety and its two subcomponents (somatic and cognitive) and its relationship with age, weight, height and body mass index. This is a descriptive study performed using a demographic questionnaire and sport competition anxiety test (SCAT) designed by Martens consisting of 15 questions. The study population consisted of 14 elite boy swimmers. The questionnaires were filled out by swimmers 30 minutes before competition. The data were analyzed by SPSS software, using pair t-test, student t-test and linear regression test. The mean score of precompetitive, somatic and cognitive anxiety was 17.93±3.25, 14.71±2.95, 3.21±0.97, respectively. The percent of somatic and cognitive competitive anxiety was not significantly different. The results showed no significant relationship between precompetitive, somatic and cognitive anxiety with age, weight, height and body mass index of swimmers (p> 0.05). Our study suggests that the swimming competition equally effects on somatic and cognitive components of anxiety.