**Thesis Type:** Postgraduate

**Institution Of The Thesis:** Turkey

**Approval Date:** 2017

**Thesis Language:** Turkish

**Student:** NAGİHAN KURNAZ

**Supervisor: **Osman Bizim

In this work "the congruent number problem" which is the oldest problem of number theory that has not yet been solved despite having studied on the solution for quite long time is discussed. Some of the studies on the congruent number problem have been done until these days is collected. The relation between the congruent number problem and ellliptic curves is given. The congruent number problem was first consider on the ring of integers then field of rational numbers and then the more general number fields than the field of rational numbers. Then the relation between elliptic curves and the congruent number problem is discovered and it is shown that the congruent number problem is one of the important application of Birch and Swinnerton-Dyer Conjecture which has been proved yet. If the Birch and Swinnerton-Dyer Conjecture is true it was derived that the problem of determining whether an integer is a congruent number is reduced to the problem of determining the cardinalty of some finite set.