Background: Insomnia is a prevalent sleep disorder among pregnant women especially during the last trimester of pregnancy with a significant morbidity and it is associated with adverse pregnancy outcomes. Aim: was to investigate the effect of walking using a pedometer mobile application on sleep quality among pregnant women with insomnia. Research design: Quasi-experimental pretest posttest non-equivalent control group design was adopted for the current study. Sample: A purposive sample of 100 pregnant women with insomnia during the third trimester over one year with inclusion and exclusion criteria, were divided equally into two groups a study group and a control group. Setting: Pelqas Public Hospital is affiliated with the Ministry of Health in the Daqahiliya governorate, Egypt. Tool: four tools were used, 1) Structured Interviewing questionnaire, 2) Pittsburgh sleep quality index, 3) Insomnia Severity Index, and 4) Supportive materials. Results: There was a highly statistically significant improvement in the sleep quality index and a decrease in the insomnia severity index after walking regimen (p=0.001).