A total of 317 carp Barbus grypus were collected during one year (1977–1978) from the Dukan reservoir of Iraq to study age, grwoth and sexual maturity. The length‐weight relationship was found be: log: W=–4.2298 + 2.6832 log L. and the condition (K) was 0.88. Back calculation was determined by using a correction factor (45.727) in Lee's equation. Predicted standard length and weight were found to be less than the actual values. The maximum increase in length was noted in the first year group, while the maximum increase in weight occurred at the time of sexual maturity. Males were found to attain maturity earlier than the females. Spawning took place during May and June.