Background Dietary supplement use is common in athletes. Besides their cost, they may have side effects on health and performance. They may also cause inadvertent doping violation.

Objective The study aimed to explore the frequency, type, believes, attitudes and knowledge of participants regarding dietary supplements.

Design KAP analysis, cross sectional, cluster sampling, year 2011.

Setting Face to face data gathering strategy from national level athletes performed based on valid questionnaire.

Participants 350 national level athletes (mean age 21.87 years) from 26 different sports fields and both sexes.

Risk factor assessment Age, sex, level of education, sports field, history of sports participation, weight, height, body mass index.

Main Outcome Measurements Knowledge was good in 36.70%, average in 59.80%, and poor in 3.20% of respondents. 65% of them either did not use any sports supplements at all, or they used less than 2 times weekly. The most widely used supplements were vitamins (m=76.9%, f=77.4%), energy supplements (m=56.9%, f=47.1%), and minerals (m=44.6%, f=57.4%). 72.1% of athletes believed in their efficacy, 40.2% experienced performance enhancement and 11.4% reported side effects. Over 60% rated their knowledge inadequate and 57.5% were eager to learn more.

Conclusions Many athletes believe in the efficacy of supplements and think they are an unavoidable part of competitive sports. Considering three aspects of supplement consumption –safety, efficacy, legitimacy, it should be focused that "optimal dietary intake is the basics for sport for life". We have to stress on education, consulting sessions, and rational prescription.