BackgroundHypothyroidism is the most common clinical disorder of the thyroid gland which is associated with an increased prevalence of sexual dysfunction even if treated with medication.ObjectiveThe aim of this study was to determine the effect of cognitive-behavioral therapy (CBT) on sexual function in reproductive-aged women with hypothyroidism.Materials and methodsThis randomized clinical trial was performed on 66 reproductive-aged women with hypothyroidism referring to selected health centers in Izeh, Iran. Data collection tools included demographic information form and Female Sexual Function Index (FSFI). Eligible individuals were randomly assigned to case (n = 33) and control (n = 33) groups using block randomization with the block size of 4. In addition to standard hypothyroidism treatment, the case group received 8 sessions of cognitive-behavioral group therapy, while the control group received only standard treatment.ResultsBefore of treatment, there was no significant difference between the mean score of sexual function and its dimensions between the case and control groups (p < 0.05). However, immediately and 4 weeks after completion of treatment, the mean total score of sexual function and its dimensions in the case group increased significantly compared to the control group (p < 0.001).ConclusionAccording to the results of this study, CBT can be effective in improving sexual dysfunction in reproductive-aged women with hypothyroidism. However, before recommending this therapy to women suffering from hypothyroidism, more detailed studies are needed to prove the effectiveness of this intervention, as an adjuvant treatment to the standard pharmacotherapy.