Duct ectasia consists of dilation of the mammary ducts and is clinically manifested as nipple discharge, which is more commonly multiductal, bilateral, and colored. To identify clinical factors that might be related to duct ectasia. A case-control study was carried out on a population of 150 patients divided into two groups. Group 1 (the experimental group) comprised 100 patients with multiductal, bilateral, and colored nipple discharge, clinically representing the nipple secretion of duct ectasia. Group 2 (the control group) was composed of 50 patients without nipple discharge. The odds ratio of duct ectasia was three times higher for current smokers (p=0.04). Likewise, smokers from the duct ectasia group had smoked for a longer time (median 25 months) compared to smokers from the control group (median 15 months) (p=0.02). Parity, history of abortion or termination, breast-feeding, hormonal contraceptive use, and history of breast abscess did not increase the risk for duct ectasia. The group of women with duct ectasia was associated with current tobacco smoking.