Background: A woman's subjective happiness is an important predictor of her adjustment to pregnancy. The emotional response and level of happiness of women during pregnancy have a great impact on the continuation of pregnancy and health behaviors during this period. Objective: This study was conducted to investigate the effect of music on the level of happiness in primigravida women. Patients and methods: The present research is a clinical trial with a pre-test, a post-test, a follow-up, and a control group. The research population included all primigravida women who were referred to the comprehensive health Centers in the city of Sanandaj in the year 2020. A total of 30 primigravida women were selected using a simple random sampling method and were randomly assigned to the experimental group and the control group. The experimental group listened to music by Kitaro for 45 minutes every night before going to bed for a period of 4 weeks. The Oxford Happiness Questionnaire and a checklist for listening to the music were used to collect data. Results: The mean score for happiness in the experimental group increased in the post-test compared with the pre-test, but the difference was not significant. However, there was a significant difference between the mean scores for the pre-test and the follow-up stages (p < 0.01). The results of the study showed that music can increase the level of happiness in pregnant women. Conclusions: Music could be used by healthcare workers in comprehensive health centers in order to improve happiness in pregnant women.