<p>This study was conducted to evaluate the effect of inulin on bowel symptoms, depression and quality of life in individuals with constipation-predominant irritable bowel syndrome. This study was designed as a randomized, single-blind, placebo-controlled clinical trial with a parallel design and a 1:1 allocation ratio. Individuals (n = 34) aged between 21 and 63 years with constipation-predominant IBS were included in the study. Individuals were randomly assigned to two groups: the prebiotic group (n = 17), which received a 50%/50% mixture of inulin/oligofructose (4.6 g twice daily, for a total daily dose of 9.2 g), and the placebo group (n = 17), which total received 9.2 g of maltodextrin per day. The intervention period was 8 weeks. Bristol Stool Scale, IBS-Visual Analogue Scale (IBS-VAS), IBS-Symptom Severity Score Scale (IBS-SSS), IBS-Quality of Life Scale (IBS-QoL) and Beck Depression Scale were administered to the participants at the beginning, 1st month and 2nd month. As a result, total IBS-QoL score increased in the prebiotic group (61.0 ± 19.4 to 77.4 ± 15.1; p &lt; 0.006), whereas total IBS-SSS score decreased (267.3 ± 56.0 to 195.8 ± 59.0; p &lt; 0.026). In the prebiotic group, significant improvement was observed in the IBS-VAS parameters of constipation status (2.2 ± 2.3 to 4.9 ± 2.5; p &lt; 0.042^group×time), psychological state (7 (2–10) to 9 (5–10); p &lt; 0.006). It is thought that inulin may have beneficial effects on reducing symptom severity and frequency and on quality of life in individuals with IBS in whom constipation is predominant.</p>