Motivation in the realm of education is concerned as one of the most important factors to support learning process and provide high-quality learning since it enhances personal growth and adjustment. Motivation is also an important factor in foreign language education and achievement. It was also emphasized in the literature that motivation and students’ language proficiency are positively internally related. So, the issue of motivation is thought to be analyzed carefully in understanding the determinants of language achievement in any EFL setting. For this purpose this study has been designed to examine the likely effect of the motivational factors on the foreign language achievement of the students learning English as a foreign language. The study was conducted at the School of Foreign Languages at a state university in 2009-2010 academic year. The data have been collected through the questionnaire (AMTB) developed by Gardner and analyzed through SPSS 11.5 for windows. The research highlighted that students in the school study English with low motivational intensity and desire to learn English. It has also been seen that gender, compulsory or optional states of the students, importance of English, high school type and achievement in foreign language studies are important factors in determining students’ motivational level while students’ previous preparatory school education and home background characteristics are not. Finally, some practical recommendations were noted.