BackgroundObesity represents a growing threat to health with multiple negative impacts including urinary incontinence. Pelvic floor muscle training (PFMT) is the first line of treatment for urinary incontinence. Both surgical and conservative weight loss results in improvement of urinary incontinence reports in obese women and we hypothesize that a low-calorie diet in combination with PFMT would result in additional beneficial effects to urinary symptoms in women with UI compared would with weight loss alone.ObjectiveTo assess the effect of a low-calorie diet plus PFMT protocol in obese women’s urinary incontinence reports.MethodsThis is a protocol for a randomized controlled trial that will include obese women reporting UI and being able to contract their pelvic floor muscles. The participants will be randomly allocated in two groups: group 1 will participate in a 12-week protocol of low-calorie diet delivered by a multi-professional team at a tertiary hospital; group II will receive the same low-calorie diet protocol during 12 weeks and will additionally participate in 6 group sessions of supervised PFMT delivered by a physiotherapist. The primary outcome of the study is self-reported UI, and severity and impact of UI on women’s quality of life will be assessed by the ICIQ-SF score. The secondary outcomes will be adherence to the protocols assessed using a home diary, pelvic floor muscle function assessed by bidigital vaginal palpation and the modified Oxford grading scale, and women’s self-perception of their PFM contraction using a questionnaire. Satisfaction with treatments will be assessed using a visual analog scale. The statistical analysis will be performed by intention to treat and multivariate analysis of mixed effects will be used to compare outcomes. The complier average causal effects (CACE) method will be used to assess adherence. There is an urgent need for a high-quality RCT to investigate if the association of a low-calorie diet and PFMT can provide a larger effect in the improvement of urinary incontinence reports in women with obesity.Trial registrationClinical Trials NCT04159467. Registered on 08/28/2021.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13063-023-07347-4.