This thesis has presented a comparative study of English and Spanish determiners. The comparison has been made at a surface level of the determiner systems of the two languages and also at a deep structure level. The reason of this comparison has been to find out how the two languages differ or have points of similarities. The points of difference have been taken into consideration to see how these differences between the two languages affect errors in writing compositions by Spanish-speaking students learning English.Some ideas have been drawn up of how constrastive analysis could help in teaching or learning a language.