© 2021 by Wroclaw Medical UniversityBackground. The non-stress test (NST) is a simple non-invasive procedure commonly used in obstetrics clinics to assess fetal health. It is important that mothers feel comfortable during the NST and that the test results are obtained quickly. Objectives. To determine the effects of maternal position on NST results and participants’ satisfaction during the procedure. Materials and methods. This was a randomized controlled experimental study conducted at the Department of Obstetrics and Gynecology Polyclinic of Erciyes University Hospital (Kayseri, Turkey) between October 2017 and March 2018. During the NST, either the supine, semi-Fowler or left lateral position was utilized. Questionnaire forms and NST tracings were collected from 275 participating mothers and analyzed. The χ2 test was used to determine whether the distribution of categorical variables differed between groups. The Kruskal–Wallis test was used to determine whether median scores differed between groups. A p-value <0.05 was considered statistically significant. Results. Most participants in the left lateral (78.9%) and semi-Fowler positions (88.4%) reported feeling satisfied compared to only 24.2% of participants in the supine position (p < 0.001). Participants also felt more comfortable in the left lateral (92.2%) and semi-Fowler positions (87.2%). In the supine position, most participants (68.7%) reported experiencing back pain (p < 0.001). There were no significant differences among groups in terms of basal heart rate (p = 0.497), reactivity time (p = 0.421) or percentage of reactivity (p = 0.676). The number of accelerations was 5.0 in the left lateral position, 4.5 in the semi-Fowler position and 4.0 in the supine position (p = 0.051). Conclusions. Our findings support the use of the semi-Fowler and left lateral positions during the NST. Participants reported high satisfaction in these positions and felt more comfortable, and no procedure-related problems occurred.