Purpose: To evaluate time-limited hydrotubation combined with clomiphene citrate as treatment for unexplained infertility. Materials and Methods: In this unblinded, randomized controlled trial of patients who had unexplained infertility, 40 patients were treated with timelimited hydrotubation (saline, 20 ml; flushed within 20 to 30 seconds) and clomphene citrate (total, 70 cycles) and 40 patients were treated with clomiphene citrate alone (total, 74 cycles). All women underwent an ovulation induction protocol with clomiphene citrate (100 mg/d orally for five days, from day 3 to day 7 of the cycle). Hydrotubation was performed after detection of the dominant follicle. Results: There were 15 pregnancies in the 80 patients (19%) (total, 144 stimulated cycles; 10% pregnancies per cycle). The frequency of clinical pregnancy per cycle was significantly greater in patients who were treated with hydrotubation and clomiphene citrate (nine pregnancies per cycle [13%]) than those treated with clomiphene citrate alone (two pregnancies per cycle [3%]; odds ratio, 5.3; 95% confidence interval, 1.1 to 25.5; p ≤ 0.05). The frequency of pregnancy per patient (total, clinical, or chemical) was similar for the two treatment groups. The frequency of live birth or abortion per cycle or patient was similar between the two treatment groups. Conclusion: Time-limited hydrotubation and clomiphene citrate may increase the frequency of clinical pregnancy per cycle in women who have unexplained infertility.