In this paper we studyq-ary codes arising from modular curvesX_{0}(11l)over GF(p^{2})and some binary codes attached to them. All these codes have a polynomial construction and have "good" asymptotic parameters: for certain values of the parameters theq-ary codes withq = p^{2} \geq 49are better than the Varshamov-Gilbert bound, and the binary codes are better than the Ziablov bounds.