Tubal patency was studied in 53 infertile women by means of colour-coded duplex sonography (CCDS) with transcervical injection of normal saline. In 47 women the patency was studied using a 2.5 MHz transabdominal transducer while in the last six cases, a 5.0 MHz vaginal probe was used. The results were compared with a conventional hysterosalpingogram (HSG) and laparoscopic chromopertubation. When the results of CCDS were compared with those of HSG and laparoscopy, there was a 92.5% agreement, that is, there was patency or occlusion of the Fallopian tubes. In addition, CCDS demonstrated all the soft tissues and their mobility. The colour signals generated by the air bubbles make it possible to demonstrate tubal patency on both sides separately. Vaginal CCDS offers a much better resolution with the advantage of lesser volume of normal saline being utilised. Tubal patency can be demonstrated in the presence of anatomical complications and requires only a small quantity of normal saline. This new tubal patency test is offered, not as a substitute for HSG, laparoscopy, hysteroscopy or salpingoscopy, but as a screening technique in the armamentarium of infertility investigations.