Objectives: We sought to determine the effects of the delayed start protocol with gonadotropin-releasing hormone (GnRH) antagonists in poor responders undergoing in vitro fertilization (IVF). Methods: This randomized clinical trial was conducted during a 15-month period from April 2014 to July 2015 in clinics in Shiraz, Iran. A total of 42 poor responders with primary infertility were randomly assigned to the controlled ovarian stimulation group utilizing the delayed start protocol (n = 21) or the traditional group (n = 21) using GnRH antagonist, Cetrotide. The primary endpoint was the number of patients undergoing oocyte pick-up, implantation, and the rate of pregnancy. Results: The baseline characteristics of the two study groups were comparable including age, infertility duration, and body mass index. The number of follicles measuring > 13 mm in diameter (p = 0.057), retrieved oocytes (p = 0.564), mature metaphase II oocytes (p = 0.366), embryos (p = 0.709), and transferred embryos (p = 0.060) were comparable between the two groups. The number of patients undergoing oocyte pick-up (p = 0.311), the rates of implantation (p = 0.407), and pregnancy (p = 0.596) were also comparable between the two groups. Conclusions: The delayed start protocol was not associated with better conception results or cycle outcomes in poor responders with primary infertility undergoing IVF cycles.