BACKGROUND: Secondary amenorrhea is a condition in which there is cessation of menses after at least one menstruation. It is a symptom of different diseases, such as hormonal disturbances which range from pituitary to ovarian origin, as well as CHROMOSOMAL abnormalities. Knowledge of the distinct cause of secondary amenorrhea is of tremendous benefit for the management and monitoring of patients. In this study, we determine the CHROMOSOMAL abnormalities in patients with secondary amenorrhea in Southwest Iran.METHODS: We selected 94 patients with secondary amenorrhea who referred to our Cytogenetic Ward from 2004 until 2009. For karyotyping, peripheral blood lymphocyte cultures were set up by conventional technique.RESULTS: In this study, 5.3% (n=5) of patients with secondary amenorrhea presented with CHROMOSOMAL abnormalities, of which all contained an X element. The CHROMOSOMAL abnormalities were:i) 45, X (n=1), ii) 47, XXX (n=1), iii) 45, X / 45, Xi(X)q (n=1), iv) 45, X/46,X,+mar (n=1), and v) 46,X,del(Xq)(q23q28) (n=1).CONCLUSION: Our study revealed that some causes of secondary amenorrhea could be due to CHROMOSOMAL abnormalities. Therefore, cytogenetic studies should be important tests in the evaluation of patients with secondary amenorrhea.