Introduction: Pregnancy is characterized by several changes in her body. These changes contribute to the emergence of low back pain, which may influence the quality of sleep during pregnancy. Objective: To compare the quality of sleep among pregnant women with and without low back pain during pregnancy, examining the relationship between two variables. Materials methods: Thirty volunteers aged between 19 and 36 years, divided into control group (CG -n = 16) and Study Group (SG -n = 14), residents in the cities of Natal, were evaluated in the second trimester of pregnancy. To sleep evaluation were used to index the Pittsburgh Sleep Quality and the Epworth Sleepiness Scale. Low back pain was evaluated using the pressure algometer, Visual Analogue Scale (VAS) and Oswestry Disability Index. Statistical analysis used the Shapiro Wilk test, Student's T test for independent samples and Pearson correlation test. Results: The mean gestational and chronological ages were 28.2 ± 3.4 years and 19.9 ± 3.7 weeks, respectively. Sleep quality was lower in SG (8.21 ± 4.8) when compared to CG (5.94 ± 1.7) and was statistically significant (P = 0.021). Analyzing the relationship between sleep quality and pain intensity, it was observed that the variables have a positive correlation between them