Objectives: This study was conducted to determine the prevalence and risk factors of low back pain in pregnancy period. Methods: The study group was a cross sectional pregnant population admitted to health centers and hospitals for routine pregnancy controls. A structured questionnaire, disability indexes and Zung depression scale were administered to pregnant women. Nonparametric tests were used to determine pain sensation before and during the pregnancy. Logistic regression analysis was performed to determine the probable factors which may lead to pain sensation and to specify its severity. Results: This study was completed with 1357 pregnant women with a mean age of 27.1 ± 9.9 years. The frequency of LBP in our study group was 734 (54.1%). Pain related restriction in daily activities were evaluated by Quebec and Oswestry indexes (respectively Kruskal Wallis; 74.561, p < 0.001, Kruskal Wallis; 70.981, p < 0.001) and a significant difference was found between those who suffered from pain and who did not. Logistic regression analysis revealed that in subjects who had pain before pregnancy had increased weight, smoking, increased maternal age, the highest Qswestry score and no assistance in their daily activities had both pain and more severe pain. A predominant decrease in disability was observed between fourth and fifth months of pregnancy. Conclusions: Low back pain prevalence in Turkish pregnant women is similar to the prevalence of pain in other countries. Oswestry disability index can be used to detect low back pain related to pregnancy and early physiotherapeutic treatment may be initiated. © 2006 IOS Press. All rights reserved.